M.U.L.E - a four-player competitive and cooperative game where you're colonizing a planet, building farms, mines, or power plants on plots, and then trading resources with the other players or selling and buying them from the store. You're striving to come in first place, but at the same time, your colony has to be successful, so if you screw everyone else over and the colony is a failure, you all lose. It has random events, like pirates showing up, the store catching fire, MULEs running away, random production increases or decreases due to weather or the like, to spice things up a bit.
Master of Orion 2 was pretty great at the time. The AI can't handle all the complexity, though.
Sword of the Stars: Complete does a better job with it, and yet somehow I've only once finished a game of SotS. Maybe it's because the AI in SotS is almost as good as me and every war I fight turns into a long slog.
Deus Ex, already mentioned, was great. I replayed that so many times, with different challenges, or trying different things to see if the characters or the story would react, and it didn't even have achievements.
Sid Meier's Alpha Centauri and Alien Crossfire - Turn based strategy on an alien planet, basically what happens to the colony ship from Civ. So much characterization and story in a turn based strategy game, it made every other civ game boring by comparison. The AI leaders actually seemed to have personalities and acted on them, warning you if you were doing something they disapproved of, or being gracious if they liked your values because they matched their own preferences (unless/until they decided to backstab you), and you could get further insight into them from their quotes in the tech tree and wonders.
Morrowind, of course. Basically what all later Bethesda games have failed to be.
P.S.
The DRM for (the first) Pool of Radiance is a
code wheel.
Did we have this thread before? I get the feeling I've done this before (and I'm leaving lots of games out for brevity's sake
).
Edit: Whoops, was missing a /.