And to celebrate, I have (naturally) created a list of characters who share voice actors with Sonic characters...ta-da

Sonic = Chris Redfield
Knuckles and Storm = Guile*
Big = Ryu
Cream = C. Viper
Cubot = M.O.D.O.K.
Blaze and Omochao = Chun-Li

Snively = Super Skrull

*Note: Guile himself does not appear in MvC3, but you get the idea...