Concerning modern games, I'd say Gothic II (spent a year playing, didn't count how many hours), Outcast, which I played for as long as I could, I simply didn't want to finish that game and be done with it, and now Fallout 3; that one I'm still playing (I only got it last November), and I'm not even halfway through it.
If you count old-school games, I've probably played more Defender, Yar's Revenge and Video Pinball on the Atari 2600 and Super C, Code Name Viper and the first Simpsons game on the NES more than would be considered healthy...
If you count old-school games, I've probably played more Defender, Yar's Revenge and Video Pinball on the Atari 2600 and Super C, Code Name Viper and the first Simpsons game on the NES more than would be considered healthy...