Dark Forces is my favorite FPS ever. My brothers and I played it constantly when we were kids. We used to go over to a friend's house to play Dark Forces 2 as well, but I was the youngest and never really got to play it very much.
When Jedi Outcast came out, I bought it right away and loved it. The levels before you get your lightsaber are a little bit boring, but they're also the most challenging, if you ask me. That mining facility is a pain in the ass on the higher difficulties. Once you get the lightsaber and become practically invincible, the game is pretty much cake.