I had the same reaction when I found out Corey Burton was the voice of Spike and Shockwave in the G1 and Animated series,
and was the voice of Dale (from Disney's Chip & Dale), Captain Hook, Buzz Lightyear (for their Disney on Ice show) to name a few.
http://en.wikipedia.org/wiki/Corey_Burton
My wife has done some voiceover work and unless a v.o. / ADR actor to has several if not dozens of voices in their repetoire then they get very little work.
