[Taqwus]

Traditional map-based 4X:
Dominions II, although the second Master of Orion game deserves a very strong honorable mention.

TBS/RPG:
Jagged Alliance 2, love/hate. Love the detail, hate the assorted lack of realism (short ranges, incredible body armor/damage tolerance, etc) and inventory management pains, plus the need to search every room, and the inane endgame. Hated the "Deidranna Lives" mod.

Other TBS:
King of Dragon Pass; love/hate. Love the detail, hate the perverse randomness where you can be very badly hurt through unavoidable bad luck in an HQ or very early bad harvests.

RTS:
Ancient Art of War, the original one. Loved utterly. Would be great to see a modern Version with configurable squad limits, modability, multiplayer, ability to run on modern-speed CPUs without requiring a circulatory system filled with caffeine and meth.
Netrek, for multiplayer.

RPG:
Fallout/Fallout 2; loved the rich stories and nOnlinearity, hated the NPC 'ally' tactical stupidities and the poor FO2 endgame.

Wasteland; very fun, although combat was very basic and the endgame was cliched and annoying.

BBS DOOR:
Hack and Slash, Usurper: very fun, brutal and competitive RPG games.
BRE/SRE: empire resource management games, essentially multiplayer updates of Hammurabi/King. Very fun.