If you don't treat yourself to reading Udo Schuklenk's blog, you should. Here's a nice piece on Hitler, Stalin, and bin Laden. Hitler was a vegetarian, but that isn't what motivated him to kill millions of Jews and others. (Unlike Hitler) Stalin was an atheist, but the millions of people whom he killed, deliberately or otherwise, died for reasons totally extraneous to Stalin's deity-free mindset. Bin Laden, on the other hand, really is motivated by his particular interpretation of Islam. To exonerate Islam, Udo says, we'd probably have to demonstrate that bin Laden's interpretation of it is wrong, which is easier said than done.
It appears to me that Islam is open to peaceful interpretations, but there is also much in its tradition that is open to bin Laden's murderous one.