Well, before I accepted Christ I had an inward conscience warning me when I was about to go awry, which I often ignored much to my sorrow.  This thing we call a conscience is evidence, albeit relatively weak evidence, of the existance of God.
 
On the subjective side... Once I accepted Christ, I had a new inward voice that guided me more clearly, and more often.  Through reading and believing God's Word I gained a new inner sense of peace.  Also, I had a tremendous inner clean pure light feeling that rose up from the depths of my soul and gave me joy unspeakable, something I had never experienced before my faith in Christ... and believe me I tried through drugs to feel good, and what I experienced through faith in Jesus put every drug I ever tried to shame.
 
On the objective side, I found evolution (biological, chemical, stellar, cosmic, etc.) to be wanting in it's answers to some tough questions.  There is some evidence for all kinds of evolution (with the possible exception of chemical evolution), but there were just too many holes, unanswered questions, and explanations that failed the smell test.  I looked at the universe, life, and my own soul and came to the conclusion that evolution simply did not answer for me.  The Bible offers an explanation for everything that satisfied me, even though it did not always line up with what science would lead me to believe.  Fulfilled prophecy, the changed lives of the apostles (not to mention the thousands throughout history that we have documentation of), lent credence to the fact of Christ's resurrection.
 
In the end, because of all the above, I am left with a faith in God that surpasses simply believing Him to exist, and reaches to the experience of knowing that He does.  Some of this reasoning/experience happened before I came to faith, but even more of it came to me after I took that leap of faith and believed unto salvation.  I don't think you can reason yourself into the kingdom of heaven, but your reason can take you to a point where you are willing to take the leap of faith if you truly want to.
 
Hope this helps;
Mike