The PS3 has the most recent issues, and launched with the highest price tag.
The 360 has the RRoD, the fewest worthwhile exclusives, and charges for their online.
The Wii has the lowest graphical capability, the worst online service, and is the source of the most forum bitching.
But, ya know what? I hate focusing on the negative.
The PS3 has a free online service on par with XBL.
The 360 has a bunch of games that, if you don't have a good PC, may as well be exclusive titles.
The Wii has a several great games from Nintendo and Capcom, (and Sega, Ubisoft, Konami...but not quite as many) as well as some niche titles that should have sold a lot better than they did. Overall, the best library of exclusives, and its virtual console provides easy access to the classics of old.
All three are great! I really wish the "hardcore" gaming community--and, while I'm at it, game entertainers, journalists, and critics--would be less negative.
The medium is improving in every area:
Games are becoming more accessible
It's getting easier and easier for independents to make a name for themselves
Some major companies are bringing older styles back into focus (thank you, Capcom!)
Others are making games bigger and more detailed than ever before
Classic games are available for download! (Nothing you're interested in coming out for a while? Go watch the Happy Video Game Nerd, then check out the Virtual Console for a game that looked interesting to you)
There's too many great games out there to be so negative all the time.