Really depends on what kind of games you like.

My favorite Star Wars game of all time is Jedi Outcast. I'd definitely recommend the entire Jedi Knight series.

Republic Commando is a great tactical FPS.

Knights of the Old Republic is a fantastic RPG.

If you're into flight sims you can't go wrong with X-Wing and Tie Fighter.

I feel I should point out though that GOG is also having a Star Wars weekend sale. They have a wider selection of titles, the best support for older titles and no DRM.

They currently have two themed bundles for the weekend: