um...the Hyperion Cantos are pretty much my favorite books of all time. I've read them about three or four times now, and they never cease to amaze me.
Ilium and Olympos were...interesting...I read them after the Hyperion books so they didn't really affect me that much, since it seemed like a sort of zanier rehash of alot of the same ideas. I've only read those two once apiece though, so I'm sure there's lots I missed.
I enjoyed the shit out of his recent historical fiction kick as well, even though alot of people seemed to not like it. The Terror and Drood are absolutely stunning. They are total departures from his sci-fi style though, so it's definitely not for everyone.
I'm looking forward to his new one Flashback but after reading some reviews I'm a little...nervous. It seems to be his worst-reviewed book yet (at least from my brief scannings of amazon) and apparently it's got a lot of conservative undertones (or overtones?) basically saying "this is the horrible future you are creatiing, liberal people" which....is fairly offensive to me for reasons which should be obvious
of course those reviews could all be bullshit; we'll see when it finally comes out, i guess