Double post. Reported.
I voted (surprise, surprise) Nintendo. I understand they're not very popular amongst the "hardcore" crowd nowadays, but they still have the best (and most) exclusive franchises. I think people still associate games like MGS and Final Fantasy with Sony, but they haven't been exclusive to Sony consoles in a while now. They have some good exclusives, though. MotorStorm, Uncharted... LittleBigPlanet has potential too. But when compared to Nintendo's line-up of first-party titles, there's really no competition.
F-Zero
Metroid
Super Mario
Mario Kart
Legend of Zelda
StarFox
Donkey Kong
Golden Sun
Advance Wars
Fire Emblem
Kirby
Pikmin
Kid Icarus
Smash Bros.
Pokémon
Sin & Punishment
WarioWare
Animal Crossing
Brain Training
Wii Sports
Nintendogs
etc.
Those last three might not get me particularly excited, but they show the diversity in their line-up. They have pretty much every genre covered.
For me, the possibility of seeing a new Metroid or F-Zero game is reason enough to buy the next Nintendo console, whatever it may be.
This has been: My Opinion.