Some of my favorites are already mentioned here, but I didn't see these ones:
PC:
- Might and Magic VI: I saw the previous ones were mentioned but this is the only one I played and I have quite good memories of it
- Heroes of Might and Magic III: one of the most addictive turn-based strategy game I ever player...
- Civilization II: ... but this one was really the most addictive in my case (one more turn... 10 hours later... one more turn); check
FreeCiv which is a really good alternative
- Dungeon Keeper: I didn't play the second opus, but the first was simply awesome; also check the
KeeperFx remaster which is as faithful to the original as a remake can be (thanks to MrFlibble for the link)
- Warcraft II: "yesh milord", "hello", "the town is under attack!", "ready to work", "zog zog", and the
amazing OST ("Your soundcard works perfectly.")
- Grand Theft Auto: Vice City: the best one in my opinion, because of if its awesome 1980s atmosphere...
Mega Drive/Genesis:
- Golden Axe: the arcade version was mentioned by Interkarma, I enjoyed especially the first one on Mega Drive
- Streets of Rage I and II: just listen the
soundtrack of the first one and remember, ooyah! (and thanks to Yuzo Koshiro for making the Mega Drive sound like this!)
Game Boy:
The Legend of Zelda: Link's Awakening: the best Zelda ever