Super Mario Galaxy Mario Kart I would recommend Metroid Prime 3, but hold off. They're putting out a 3 pack soon with Prime 1 and 2 redone for the wii and 3 is included. These are must have games. Ghostbusters (yeah, so they look like The Incredibles, but it plays amazing... comes out June 16th) Raving Rabbids if you want some mindless hilarious fun. Wii Fit... the games on it are fun... plus seeing wife/girlfriend do yoga? BONUS.
there's too much good stuff to even list for the ds. you will find games that you like for it, no problem. tell me what type of games you like and the it'll be easier to list things. as for the wii, everything everyone's listed has been pretty much spot on. super mario galaxy smash bros brawl punch out mario kart wii zelda twilight princess metroid prime trilogy is coming soon, skip 3 and wait for this okami if you don't have the ps2 version no more heroes madworld zack & wiki dokapon kingdom is probably the best party game ever made