SM64, Perfect Dark, Goldeneye, Turok, F-Zero X, Starfox 64, Mario Kart 64... Oh, Pilotwings 64, Ocarina of Time, Majora's Mask... the list goes on... and on... and on...
Overall, probably F-Zero X (Finally beating the final ghosts on Rainbow Road), or Starfox 64 (I'VE BEEN WAITING FOR YOU, STAAAARFOX!)
No, wait. Starfox 64 wins it easily. Leon's voice. Just... Leon's voice.... And who didn't love duking it out with Starwolf for the final time on Expert, nailing them all with pinpoint precision as you hear your teammates screams for help fade out. Pigma: "Your dad screamed real good when he died." BLAM BLAM, NUKE, SOMERSAULT. You scream, sucker. Slippy: Whoa, help me!" Die, frog!!! "AAAAAAAAAAAAAaaaaaaaaaaaah!!!" Yeah, I killed him. Well, Andrew always fell next, then Leon would slaughter Falco and Peppy (alright, I helped him kill Falco... and maybe Peppy.) I would get my revenge as slowly as possible, wallowing in the awesome voice acting before annihilating him with a swarm of lasers. Finally, I would utter the GAMING family's traditional phrase, (to which my brothers would grin),
"Just you and me, STAARWOLF.
After running literal rings around him, I would waste my entire collection of bombs on him. BOOM-KABLAM-KAPOOM, then "NOOOO!!! THIS CAN'T BE HAPPENING!"
Chronologically, the first game I played on it was Goldeneye, which is amazing, needless to say. Perfect Dark was different. Not better. Those were the glory days for FPS games. Where the level designers actually respected you to be able to figure out where to go without glaringly obvious signs everywhere, or having regenreative health. Never have I felt such tension/orgasmic pleasure at finally beating cradle on triple agent.
In terms of quality, I cannot really decide whether I preferred this or LOG OOT. Definitely my favourite Zelda ever. However since they are such different genres, it's like comparing apples and oranges.
For the sheer enjoyment factor, I think I'll have to go with mario cart though. Some of the fondest memories of my brothers and I involved that game. So much fun on split screen.