Am I the only person on these boards who loved the Cyberpunk 2020 Rules...Before the R.Talsorian rules mixed with the Hero systems to become the d10 systems (I think, anyway). Cyberpunk campaigns were the only ones we played that lasted for a long time (the longest one being a bit over 2 years). My old Cyberpunk referee moved to North Carolina, so I haven't played it in about 3 years, but I loved it so much.
If I could could choose another system I'd have to agree with Doc Klueless on Fading Suns. I've never actually got to play it, but i've read the rule book and a few of the setting books a bunch of times and I have to say out of all the sci-fi settings that I've seen it's definetly my favorite.
Exalted seems pretty hot, too.