I read the book before the movie came out (I was 12 at the time; I vividly recall begging my mother to take me to the bookstore to buy it, at which time she presented it to me because she'd already bought it for me for Christmas or my birthday (not sure what month it was)). So, I have always understood the movie in light of the book. And yet, I love Kubrick's films -- he's my favorite director, and I think I would have loved 2001 even without having read the book. In that case, I think my interpretation would have been a lot like Ebert's, although I wouldn't have been able to express it as well. But, I'll never know, because I simply didn't have the opportunity to have that experience.
I think if you did have that experience you would hate him :)
I watched the movie, thought it was horrible and incomprehensible, read the book, then watched it again and enjoyed it - somewhat, I kept getting annoyed at how unwatchable it was without the book knowledge. But except for the warp scene the visuals were great.
