Sid Meier's Alpha Centauri. possibly with its expansion pack, Alien Crossfire.
it's basically Civ 2, but colonizing another planet. i loved this game back in high school, and need to get another copy.
used to be incredibly expensive and rare (especially the expansion), but then EA rereleased them for a little while in a "laptop collection" bundle with Red Alert 2, Sim City 3000, and Tiger Woods