Age of Empires II: The Age of Kings

The Good
It will keep you playing for months the multiplayer is incredibly balanced all the civilizations fight well and strategy is abundant. Back when this came out the graphics where great as well. Choose from the mongols, chinese, britons, franks, saracens, etc. A lot of diversity with each civilization having their own interface and own sounds. I really learned a lot of history from this game as well. I'll never forget how Barbarossa died. The rated system on the zone is what kept me coming back, the numbers were well calibrated and you only got a lot of points for when you really won. Singly player was fun too, though not nearly as fun as multiplayer. The civilizations each possess their own special units which totally change their position on the battlefield. Playing on custom maps was also really fun. You can choose from random map, deathmatch, custom map, king of the hill, and a whole slew of other styles. This is truly a strategy classic.

The Bad
The zone system they used online was a little buggy, and it didn't contain cheaters to well either. I doubt they've fixed it either, the net's best hackers were addicted to this game.

The Bottom Line
A really great strategy game, an unforgetable classic. It also serves as a usefull learning tool about midieval warfare. Truly a groundbreaking game.