Dark Forces was just incredible back then. I was a Star Wars fanatic in those days, reading all the novels, mags, following the special edition movies, prequel news, and playing all of the games. Dark Forces was the first official SW first person shooter. There was Star Wars Doom before that tho and it was pretty good!
DF just has great atmosphere to it, brought from an obviously talented group of developers. The original music was incredible, with Bajakian, Land, and McConnell doing brilliant work just like with TIE Fighter. Man those were the days! It was just pure euphoria to be able to explore SW in the 1st person for the first time. I would love to have that kind of quality effort be put into a SW game again. LucasArts isn't even remotely the same company anymore though.
I still think DF is the best in the series. It has the premise that I most enjoy. Mercenary Katarn, hardcore ex-Imperial, but just a regular guy. The game is very military and very dark. I just dig that kind of sci-fi.