Probably my most played console (historically, but not at present). It was hot in middle school and high school and was in high demand basically until the Xbox, or Halo ousted Golden Eye. I feel like the N64, and by extension its games, can't be properly valued out of context. The N64 was a multiplayer console, and really the first one ever developed with this in mind. Some of the best games on the console and the ones with the fondest memories were the ones that were played with friends at sleep overs and parties. The rest were really just ground breaking 3D innovators.
My favorites, in no particular order:
Super Mario 64
DOOM 64
Mario Kart 64
Turok 1,2, and Rage Wars (my friend group really preferred this to Golden Eye; more violent and better weapons/characters)
Wayne Gretzkey's 3D Hockey (best hockey game, period...)
Gauntlet Legends (Probably one of my favorite co-op games of all time)
San Fransisco Rush
The Legend of Zelda: Ocarina of Time
Starfox 64
Worms Armaggedon (really wish I had kept my childhood copy...)
Runnerup special mentions: Mario Tennis (still the best Mario Tennis game IMO), Super Smash Bros., Starcraft 64, and Rampage World Tour (played the hell out of this game with friends)