N64, but for personal reasons. I have too many memories with it. Mario 64, Ocarina of Time, Majora's Mask, Jet Force Gemini, Turok trilogy, Banjo Kazooie, Bomberman 64, Smash 64, Kirby Crystal Shards, Yoshi Story, Diddy Kong Racing, Ogre Battle 64, etc etc etc were the games that ruled mu childhood.
I acknowledge that the PSX had the better overall library, but I mainly played the N64 during that time. With that in mind, the console has a special place in my gaming history and for that reason alone I must pick the N64.