Yo, Me and All,
(I hate replying to myself!)
I haven't posted for a while because I've actually been playing the game! Turns out that, for me, the Catalyst 5.2's did the trick. I installed those Thursday night and everything's been smooth sailing since. (w00t) I played for five hours last night straight with no issues. I had a few graphical artifacts (textures being replaced with matte black depending on the viewing angle) at Peragus, but after quitting for the night and starting the next day, they seem to have gone away.
So, my experience:
Cat 5.1 - sucky, constant crashes