IGN gave Super Mario Galaxy 2 a 10 out of 10. But IGN always gives out padded scores. Well, Gamespot gave it the same score.
For reference, here are the other games that have received a 10 from Gamespot: Grand Theft Auto IV, Metal Gear Solid 4: Guns of the Patriots, Tony Hawk’s Pro Skater 3, Chrono Cross, Soul Calibur, and The Legend of Zelda: Ocarina of Time