I'll go with the games I've spent most time playing over the years as well. A lot of these won't be on other lists I would guess! Still have games like Fallout 3 & 5, Skyrim, Arkham Asylum to play so they could replace some of these in the next year!
Zelda Ocarina of Time - Addicted to this game as a kid
GTA V - Favorite of the series
Elders Scroll: Oblivion - Superb, still have Skyrim to play and so looking forward to getting hold of the remastered version!
Red Dead Redemption - Such a good game and looking forward to playing it through again before the new one is released
Conflict Desert Storm - This game and the series as a whole, I spent hours playing these through in multiplayer with my brother. I would guess it has aged horribly.
Football Manager - Stuck this one down as an overall, CM & FM combined I would dread to think how many hours I have spent on them combined
Witcher 3 - Still playing this and will be for a while, ridiculously good game with a huge amount to do
Goldeneye - The ultimate FPS
Diddy Kong Racing - Again I spent hours and hours playing this back on the N64
Mario 64 - First game I ever owned and was blown away by it