While I’m not a fan of the overly general “favorite” label, if I had to choose one game? I’d say Majora’s Mask. It’s very close though between that and SM64, but for different reasons. SM64 is endlessly replayable and is truly among the greatest of 3D platforming (despite being a pioneer for the genre), whereas Majora’s Mask sucked me in unlike any game I’ve ever played prior.

Also Banjo is definitely up there.

Diddy Kong Racing out of the ones I've played. Far better than MK64 imo.

GoldenEye was what I played the most, Ocarina of Time is the best game on it and one of the best games ever made. My favorite not highly rated games were NBA Hangtime, Wayne Gretzky 3D Hockey. My favorite 1st/2nd party game that wasn't one of the main games was Blast Corps. The game I never played, that I wish I had is Ogre Battle 64.

Conker’s Bad Fur Day. Multiplayer was great, too. A number of modes that you just don’t see in other games.

The one with the Wipeout flying cars. Can't think of the name right now but I know people will know.

Donkey Kong 64

A lot of great games to pick from, but I can't look past Ocarina of Time.

That and Pokémon Snap.

The N64 had so many incredibly good games that is really hard to choose: Super Mario 64, Ocarina of Time, Majora's Mask, Perfect Dark, Jet Force Gemini, Conker's Bad Fur Day, Paper Mario... Even the "less ambitious" ones were peak in their genre at the time: Wave Race, F-Zero, Smash Bros...

But, if I had to choose one, It would be Majora's Mask. It's world, and the deep of his story and characters were (and I think still are) unparalelled. No game has provided the kind of catching stories tied to daily/hourly routines and the 3 day cicle like it did. I still wish someday we'll get a game with a 5 or 7 day cicle where you can explore not only the world but it's inhabitants routines for each day.

Aside of it, JFG and Conker were also very dense, complete and original on their proposal, but the charm, mystery and character of Majora's is of a diferent kind, really special. Plus, it's temples were awesome, even more complex and with more interesting mechanics than the ones in Ocarina. And Link's transformations, and enemies, and horse and goron and even dog races, and... God, there were so many awesome things on it.

I recognice the importance of SM64 and OoT as pioners, genre and mechanic definers, but MM took story, mechanical and gameplay depth one steep beyond.

Conker BFD overall.