Bertrand Russell's Why I Am Not a Christian is one of the most well known lectures in defense of the rejection of Christianity.
Here are some Christian responses to the lecture. I'll be adding more as I find good responses.
Why I'm not Bertrand Russell by Steve Hays
Apologetics in Practice by Greg Bahnsen (parts 1 & 2)
A Review Of “Why I Am Not A Christian” By Frederick Meekins
Related Blogposts and Links:
Book Reviews of Recent Atheist Authors by Christian Apologists
"My Father, Bertrand Russell"
Why I Believe by Steve Hays
Part One A Positive ApologeticWhy I Believe in God by Cornelius Van Til (YouTube audio)
Part Two I'm Glad You Asked!
Love the Lord With Heart and Mind
(See especially Steve Hays' contribution)