The top one for me is definitely TIE Fighter... awesome game, awesome soundtrack, awesome mission design. It enhanced what X-Wing started in practically every possible way.

I did play a bit of Dark Forces, but it never sucked me in as much as Jedi Knight did when it came out. Technically it was incredible for its time (sure, there was Quake, but JK had the SW bonus added to that). And just as it was between TF and XW, Jedi Outcast improved on Jedi Knight just as much.

Knights of the Old Republic was fantastic too, and Knights of the Old Repuclic II - The Sith Lords (which was much weaker than its predecessor, suffering from its rushed release) is the last Star Wars video game I've played.

I still hope there's a chance for a next-gen space battle game set in the (OT) Star Wars universe.

And since we're talking "games" and not only "video games", I can highly recommend the X-Wing Miniatures Game, which I'm playing a lot lately.