If you enjoy Multiplayer with your friends and family, get the wii. Also if you like the cartoon, enchanced, "feel-good" graphics such as mario get the wii. Wii is basically made for everyone, even for your grandparents.
If you enjoy HD next gen graphics, get the ps3. Alot of action, violent type of games can be found in the ps3 library (im not saying all of them are violent/action, but most of them are).
In my opinion get the wii, it"s fun in general and you can have a good time alone or with people around you with some good laughs. Think about the motion sensor, and super smash bros with your friends

. I also consider the wii to give u more social status than the ps3. Both give you fun entertainment, but i believe the fun from the wii is something to remember 10 years from now.
i would recommend the wii