It's rare that I actually have a connection to a movie because of the books, but having listened to 2001 and all four of its sequels on audiobook, I'm pretty attached. The thing is, I'm not completely gaga over Kubrick's adaptation of 2001: A Space Odyssey. Frankly, if I hadn't listened to the book first I would have probably been completely lost at the end. He really left the final moments of the movie open to discussion and analysis, which is great, but when taken as a series it really helps to have a better understanding of that last big event before moving into 2010: The Year We Make Contact. And I think that's pretty important, because 2010 is easily my favorite of the series.
Honestly, when I finally decided to sit down and watch the movie version, I wasn't expecting it to be very good. It seems like everyone has forgotten that there's a sequel to a movie that is widely considered a classic. That and the fact that Kubrick had no part in it made me a bit wary, but I was pleasantly surprised.