2001: A Space Odyssey was, is, and will be my favorite book evar! I first picked it up simply browsing at the library a few years ago, and because I'm a big science fiction fan, I read it thoroughly and carefully.
I have got to say, it is the most carefully, beautifully captivating Sci-Fi novel I have ever read, and I've read a lot. Other books are either too much philosophy or too much like a swords and sandals epic. 2001 was a mix of both, and I loved it.
I haven't actually seen the movie, although it's been sitting in my hard drive downloaded *ahem* for a while now. You've reminded me of it, and I think I'll watch it now.
BTW, my favorite line from the book is the "Oh my god, it's full of stars!" one. I know it's a bit overrated, but that was a monumental point in the book.