The title of this essay asks a good question. Does Christianity need to be defended? If Christianity is so readily believable, as Christians maintain, why defend it? As we will establish, it is not for our sakes or even for Christianity's sake that we defend our faith in Christ. The ministry of apologetics is a service to the unbeliever and not an actual defence of that which truly needs no defense. See also, If Christianity is true, why does it need so much defending? at Christian-Thinktank.com. This same site also provides a good essay giving eight reasons for apologetics. And a really good essay about the Church's failure to realize the importance of apologetics can be found here at Tektonics.org.
First, what is apologetics?
The short answer is: It's the branch of theology that is concerned with defending or proving the truth of Christian doctrines. A much more detailed answer is here at Christian Apologetics and Research Ministry ; a very fine site.
Do we need to defend Christianity?
C. S. Lewis writes:
"We who defend Christianity find ourselves constantly opposed not by the irreligion of our hearers but by their real religion. Speak about beauty, truth and goodness, or about a God who is simply the indwelling principle of these three, speak about a great spiritual force pervading all things, a common mind of which we are all parts, a pool of generalized spirituality to which we can all flow, and you command friendly interest.
But the temperature drops as soon as you mention a God who has purposes and performs particular actions, who does one thing and not another, a concrete, choosing, commanding, prohibiting God with a determinate character. People become embarrassed or angry. Such a conception seems to them primitive and crude and even irreverent. The popular ‘religion’ excludes miracles because it excludes the ‘living God’ of Christianity and believes instead in a kind of God who obviously would not do miracles, or indeed anything else." 
When we get to the heart of most skeptics' stubborness, we find they aren't necessarily opposed to belief in God per se. They actually oppose what they suspect He stands for. Specifically, they oppose His authority over mankind. And, in many cases, they oppose their personal, twisted caricature of what Christianity truly is.
Ask the average skeptic or anti-theist to tell you of the god he/she doesn't believe in and you will most likely not believe in that god either. The heart of their problem is the problem with their heart. They are so set on not being ruled by God, they haven't bothered to truly find out who the God of the Bible is. I posit that, whether it's disbelief or misbelief we find, it's a worthwhile ministry to help people to understand the truth about Jehovah God!
An atheist's heart is exposed
I was once asked a question. The questioner was a particularly profane and blasphemous atheist, who didn't really want an answer, but sought only to heckle a defender of Christianity. He asked me why I bothered to defend Christianity. He went on to state that Christianity wouldn't need defenders if it weren't such an evil institution.
I found this question quite engaging. It did not engage me in the way our atheist friend meant for it to, but it did provoke reflection. I reflected upon why he ‘felt' that Christianity was an evil institution. Subsequent colloquy revealed his fractured reasoning. He cut loose with the usual profane venting about the Spanish Inquisition, the Crusades, and the allegations that Hitler was a Christian. See articles here and here for answers to that allegation.
What did this exchange produce? Well, it led to our atheist friend answering his own question. As I see it, all his snarling accusations demonstrated precisely why Christianity should be defended. It must defended for the sake of those who disbelieve and misbelieve. In essence, Christian apologists are defending unbelievers from themselves.
In Hebrews 5:1,2 we read: "For every high priest taken from among men is ordained for men in things pertaining to God, that he may offer both gifts and sacrifices for sins: Who can have compassion on the ignorant, and on them that are out of the way; for that he himself also is compassed with infirmity."
Verses like these should be reflected upon by any apologist who is considering hanging up his/her arguments. A minister/servant of God is called to intercede on behalf of those who sin and try to draw them to Christ. This is the reason I don't like to engage in heated, petty debates where personal attacks are launched. This activity is not Christ-like and it doesn't win anyone to Him.
So, how are we to approach this problem?
The greater weight born in Christian apologetics is not carried by the scholarly defense of Biblical text. And it's also not carried by the efforts of those who present scientific data to support theism's assertions that we don't live in an accidental universe or that Earth's life forms didn't create and develop themselves.
Neither does successful Christian apologetics ride upon the back of the complex philosophical wrestling matches between us and proponents of other religions. The heart and soul of Christian apologetics exists in getting people to see their need for a Savior. I posit that, if you can get a stiff necked unbeliever to see their lostness, you have all but won the battle.
Unbelievers hide from God behind their criticisms of Christianity
There is a satanic smoke screen used by those who don't want to see the truth about right and wrong. Secular Humanism, Moral Relativism, and plain liberal licentiousness are at the heart of this soul damning problem. Non-Christians are either grossly misinformed or deliberately ignorant regarding the things of God. Just like our aforementioned friend, so many deliberately define Christianity by its abuses and its abusers.
They don't care to hear about or acknowledge the many charitable efforts that Christians are engaged in worldwide. No, and they are even less interested in the boundless testimonial evidence of lives saved from the brink of destruction by Christ's love and power.
They callously ignore stories of Christians' loving attendance when disaster strikes in the lives of individuals or even entire nations. Again, they'd rather focus upon only those instances where Christendom received the proverbial ‘black eye' because of the failures of one or more persons who are only ostensibly Christian.
Are we saying here that no genuine Christian ever fails? No. The fact that all men still possess a certain propensity for failure only shows how much we all need Christ's oversight. Besides this, what sense does it make to throw out a baby with the bath water? Why turn your back on Christ because of the intermittent failures of His people?
Why is it seemingly impossible to get skeptics to divorce bad human behavior from perfectly good theology? Apologists and evangelists try ardently to get unbelievers to look at Christ and not fallen mankind. However, their efforts are often in vain. One hates to leave people to their own destruction, but we have no alternative once we've done all we can do. Even God Himself doesn't "make" anyone accept the truth of the Gospel.
Many are those who follow the broad path to perdition. They look prejudicially at world history and ferret out instances where villains have done horrible things under a malevolent banner of some twisted form of pseudo-Christianity. Though one may try time and again to point out that these characters were actually motivated by money and political power, unbelieving critics won't hear of it. Their minds are made up and they adamantly refuse to give credit where it's due.
They launch screaming invectives and mordant mumbles at every one who dares to name the name of Christ. Look at any internet discussion forum and you will see "reasonably" intelligent people acting as if they live to punish people for their beliefs. This is the type of stereotyping that our modern, politically correct society allegedly abhors.
Yet, the same multi-cultural secularists, who preach about acceptance, callously deride believers and seek to eradicate all mention of Christ from the world. Where is the politically correct openness and acceptance in this? And to think that it's Christians who are called intolerant bigots.
Why doth the heathen rage?
If unbelievers truly think Christianity is some fantasy religion, why does the mention of Christ's name anger unbelievers so? One may try and dissuade a person from believing that the moon is made of green cheese, but it doesn't make sense to hate them for believing it. So, why would any "intelligent" person fight against others simply because they believe in Jehovah God? The reason lies in the injurious realm of carnal thinking. The moral and ethical precepts of true Christianity are hateful and binding to the secular mind.
Rom. 8:7 says, "Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be." This, in a nutshell, explains the innate, anti-Christian hostility of atheistic and liberal thinkers. As long as people of God proliferate the world, they know that their secular political agendas are going to be opposed. Are there any anti-theists who will admit this? Yes.
Aldous Huxley, son of Thomas Huxley, writes:
"I had motives for not wanting the world to have a meaning; and consequently assumed that it had none, and was able without any difficulty to find satisfying reasons for this assumption. The philosopher who finds no meaning in the world is not concerned exclusively with a problem in pure metaphysics. He is also concerned to prove that there is no valid reason why he personally should not do as he wants to do. For myself, as no doubt for most of my friends, the philosophy of meaninglessness was essentially an instrument of liberation from a certain system of morality. We objected to the morality because it interfered with our sexual freedom. The supporters of this system claimed that it embodied the meaning - the Christian meaning, they insisted - of the world. There was one admirably simple method of confuting these people and justifying ourselves in our erotic revolt: we would deny that the world had any meaning whatever." 
Here, Huxley openly admits that his aversion to Christianity was part of a particular agenda. It was not that he couldn't believe in Christ, but that he didn't want to. He openly states that he saw Christian morality as an impediment to erotic whimsy. So, Huxley remained deliberately ignorant of what serving Christ would do to change his life. Having said that, isn't it ironic that he also made the following statement?
"Most ignorance is vincible ignorance. We don't know because we don't want to know. It is our will that decides how and upon what subjects we shall use our intelligence... No philosophy is completely disinterested. The pure love of truth is always mingled to some extent with the need, conciously or unconciously felt by even the noblest and the most intelligent philosophers" 
Ironically, Huxley speaks of willful ignorance when his own thinking epitomized what it meant to be willfully ignorant. By the way, Huxley is wrong here. Willful ignorance is the most in-vincible ignorance of all! People who don't want to know something will not know it. There are none so blind . . .
I humbly adjure all skeptics and atheists alike to consider the following point closely. No matter what you've experienced in your life, no matter what you've seen other humans do, never stop looking for the truth. Don't let outrage and disillusionment dissuade you from finding what true Christians have already found. A true Christian isn't out to gather people to himself, but to Christ. We seek to gather people to Christ for Christ's sake and theirs.
In fact, let the following scripture speak for us regarding pure intentions. In 2 Corinthians 4:3-5 we read, "But if our gospel be hid, it is hid to them that are lost: In whom the god of this world hath blinded the minds of them which believe not, lest the light of the glorious gospel of Christ, who is the image of God, should shine unto them. For we preach not ourselves, but Christ Jesus the Lord; and ourselves your servants for Jesus' sake."
C. David Ragland, Jr.
 C. S. Lewis, "Miracles: A preliminary study"
 Aldous Huxley, "Ends and Means, 1937"
 Aldous Huxley, "Ends and Means, 1937 pg. 270-272"