PS3: Free Online, XMB, Love the current and Upcoming exclusives.
Wii: SSBB, LoZ, Very Small
360: It has a nice green light in the front... well... if it stays green anyway...

Wii: Nintendo games ( the main reason I buy any Nintendo console), VC is a retrogamers dream ( and it's legal)

360: Xbox Live ( the console just doesn't feel right without it), Huge library of quality titles ( many are still exclusive)

PS3: The most powerful console ever created (and much of it has yet to be tapped), Lots of innovative PSN ideas ( truthfully the best feature on the console imo)

PS3- Games and Blu ray
Wii- Games and motion controls
Xbox 360- Games and Xbox Live

Wii - Animal Crossing

360 - some of the games

PS3 - free online/games

I'm gonna stick with ONE feature per console.

Wii: Bowling
360: Xbox Live
PS3: Blu-ray

Wii - John Lucas

360 - Dodece

PS3 - DMeisterJ

Wii: it's refreshing
360: Love its library
PS3: Great media player

Wii - It has Nintendo games

PS3 - powerful, multipurpose, lots of potential

360 - Great game library, easy to develop for

Funny because one of those don't actually own the console!

Anyways

Wii: Nintendo Console ~Enough Said

360: Library and Online

Ps3: MGS4 and Bluray

Wii: Has expanded the market, converting a lot of non-gamers into gamers. And puts the focus on game design/fun instead of graphics.

360: A TON of games with a lot of variety. There's no way I can hope to play every game I'm interested in... which is kind of a problem, I guess, but it's a good one!

PS3: Sony has really lifted its game re: first party stuff. I think they have a lot of genuinely neat games out/dropping soon (LBP, the PixelJunk games, Last Guy, etc.) and hopefully have much more in the works.