Must have wii ware games

wii fit, COD5 with the wii light gun, Shaun white Snowboarding (for the wii balance board),Skate it(also for the wii balance board).

Since the question was about WiiWare games I figured I would actually answer with WiiWare games. Best ones I can think of off the top of my head are World of Goo, Cave Story(not out yet), Mega Man 9, Lost Winds, and the Bit.Trip games.