This is actually a really easy question to answer. Aside from Skyward Sword for Wii the system is completely dead to gamers.
Nintendo is really not making much new they have moved on to Wiiu.
So the question really is do you want a growing library of games or a completed library of games. Also do you want an online community and good downloadable content or do you want no intereaction and a limited selection of titles for download. Do you have an HDTV if so do you want HD gaming or non HD gaming? If the following is true then get that console...
Wii: I don't want more games to come out I am happy with what is there, price matters more, I hate online, downloadable games don't really interest me, I don't want to play games multiplayer and I love waggle.
PS3: I want to see more original content, I love free online, I want to be part of a community of gamers, I want good content for download, multiplayer games yes please and I can afford a slightly higher price point.