-Planescape: Torment. It's so immense and compelling. Morte is one of my favorite characters.. Ever.
-Outcast. Although I really havent played it myself, I've heard some outstanding details about it. Like the revolutionary A.I.
-Megaman 1. I really like it. Some might say that Mm 2 is better, but what really boosted the series was the megabuster in Mm 4. Megaman 3 has the best title music though (and that makes any difference?..No)
Now, I'm getting down. hard.
-Deus Ex 2....(please don't hit me.. (and stop kicking too)). Comparing it to the original one would be genocide(or some cide whtvr). But a had fun with its multiple bugs and absurd design flaws. Every one should play the last level. I had killed one of the factions (knights templars, if i recall it correctly) agents and sabotaged it's doings through the whole game and in the final stage I did a tiny little job for them... And I say, they forgot everything else.. Maybe that's the future.