Both of them have ace versions of mario kart, trhe DS one ebing slightly better. Other than that I have listed a few good games for each.
Wii
No More Heroes (Teen Action Game not suitable for younger kids)
Sonic and Mario olympics (Family button basher)
Mario Party 8 (party game)
Wario Ware (Party Game)
Call of Duty 3 (shooter)
DS
Final Fantasy Crystal Chronicals (action RPG)
The world ends with you (RPG)
Nintendogs (pet sim)
Brain Training
Pokemon series (RPGs)
-Frank
