"Tom Kenny"
For some strange reason this guy looks like he could provide high squeaky voices for cartoon characters without even trying. Anyway, Tom Kenny provides the famous, and annoying voice for SpongeBob SquarePants and the forgotten Heffer Wolfe from Rocko's Modern Life. Click here to see his complete credits from IMDb.

"Cree Summer"
Who would have thought that Freddie Brooks from A Different World was such a gifted voice-over actress. Cree Summer gave us the voices for Penny from Inspector Gadget and little Susie Carmichael from Rugrats. Summer is still active in voice-overs and has projects lined up. Click here to see her complete credits from IMDb.

"Christine Cavanaugh"
If there was one woman who only provided her voice for wimpy and nerdy cartoon characters, Christine Cavanaugh would be her. Chuckie Finster from Rugrats and Dexter from Dexter's Laboratory were all vocally created by a now-retired Cavanaugh. Click here to see her complete credits from IMDb.