(I've just had a quick skim through the thread so my apologies if I've missed anything or these points have been made already)
Christianity and Islam have a long and acrimonious history. As I mentioned above, the Crusades were response to Islamic armies invading Judeo-Christian territory, and recent events such as 9/11 have made it come out into the open again.
1. Islam rose through military conquest, spreading through the land which was Holy to both Christians and Jews. By contrast, Christianity was illegal for the first 300 years and many Christians were killed for their faith.
9snip)
2. Muslim scholarship was at it's height during the Medieval period, and exchanged many of their ideas with European Christians. Around the 10th century however, Ash'arite philosophy began to take hold - a philosophy which claimed that "To search for ends and reasons in His laws is not only meaningless but also grave disobedience to Him." This resulted in the gradual loss of any kind of science and theology in Islam until it became the mess it is today.
See
"The Closing of the Muslim Mind"
3. Slavery - The Arab slave trade took roughly the same number of black slaves as the American slave trade did (roughly 11-12 million) and a smaller number of white Christian slaves (roughly 1.25 million).
See
BBC.co.uk - British slavery on the Barbary coast
By the way
SmellsLikeCurlyFries, I think this is the video you're looking for:
SURPRISE! Dick Cheney Admits Osama Bin Laden Wasn't Directly Involved In 9 11 - YouTube