The games that I've played the most and gained the most enjoyment out of over these past few years would have to be:
Streetfighter 2 Turbo (Sega)
Doom 1 shareware (I was SOOO impressed and excited the first time I played that - it was on a P90 as well

)
Half Life
Rainbow 6/Rogue Spear (I played Rainbow 6 online for a year solid, and Rogue Spear almost as long. They're still the most fun I've ever had in online gaming, and the community in general was great.)
I'm now board of Rogue Spear. I play CounterStrike quite a lot, which is fun, but IMHO not as good as Rainbow 6 when I was really into it. Also play a bit of Quake 3 and Unreal tournament.
I'm holding out for Team Fortess 2 though. I hated the first one, but the second looks great. Here's hoping that Valve can deliver the goods. This year would be nice as well
