No reason to buy one really. Most of the good (10m+) games this gen are on the Wii. There are many innovative games from Nintendo that take up most of my play time and are fun to play with friends who don't usually like playing games. I see no need to buy a last generation console with better graphics, especially when both Sony and MS feel inclined to rip off Nintendo's ideas over and over. I'm a mature gamer so I don't want to play shooters, sports, or crappy rhythm games. With virtual console the Wii has a better library than any other console, so I don't understand why people pay more money for their console just to play less games. Local multiplayer is where it's at, so I don't care about online play because I have friends.
I was thinking about getting a ps3 for a media centre, but it sucks for even that because you can build a HTPC that does that better.