For me that would be the Nintendo 64. Why? Because:
- Super Mario 64
- The Legend of Zelda: Ocarina of Time/Majora's Mask
- Banjo-Kazooie/Tooie
- Goldeneye/Perfect Dark
- Pokemon Stadium 1/2
- Mario Kart 64
- F-Zero x
- Mario Party 1-3
- Paper Mario
- Jet Force Gemini
- Killer Instinct Gold
- Super Smash Bros.
- Conker's Bad Fur Day
- Diddy Kong Racing
You can't argue with such amazing quality.