2010: The Year We Make Contact.
Let's face it, 2001: A Space Odyssey was terrible. It was incredibly slow and made no sense - though the music was superb. However, what really did it in was the horrid 20-minute ending montage... thing. That movie felt like it was meant to be watched while on acid, and since I don't do acid, I didn't really appeal to me.
But 2010 is a completely different story. It has plot, and interesting characters, and tension between said characters, and everything! It even has a sad, tormented supercomputer. I love 2010 and gladly recommend it to people, but I immediately warn them not to bother with 2001.