He’s ok but Rich Little was the best!
Another good one was a SNL episode where Kevin Spacey did a bunch of fake screen tests of famous actors trying out for Star Wars.
Rich Little http://www.youtube.com/watch?v=78sSn3E_Vvc
IMHO, Frank Caliendo is better than Rich Little. Caliendo is as good a technical impressionist as Little, but is more of a natural comedian.
http://www.youtube.com/watch?v=kAMIlPudalQ
My favorite was Rich Little doing Jack Nicholson as the President of the United States - "I've got one finger on the button, and one finger for Mr. Gorbachev..."
Of course I was a teen in the 80s when I saw it, must be why it stuck.