I'm having a retro moment! Ok, this list took me like an hour to come up with but here goes (there was just too much choice!)
1. Super Mario World (snes)
2. Street Fighter II (snes)
3. Legend of Zelda (n64)
4. GTA 3
5. Super Mario Kart (snes)
These games were just so awesome! I was a big fan of nintendo and all their games had so much quality put into them. I remember playing mario world for months, multiplayer on mario kart was so awesome even in the days of 16 bit!
Infact, looking back I think the original games (launch games) such as wave race for the n64, mario kart etc are still more enjoyable than some of the recent releases.
1) Starcraft (god of all multiplayers)
2) Counter-Strike
3) Vice CIty
4) Halo 2
5) Unreal Tourney (nothing specatacular but fun as hell at Lan Parties)