When I was growing up, Canadian-born Rich Little was about the only impressionist I could name. Come to think of it, he's still one of the only people most people can name in this niche area of comedy. Sure, Saturday Night Live has had great comedians over the years who have done great impressions (Dana Carvey is probably my favorite), but they're not primarily known as impressionists.
At 71, Little has just become a naturalized US citizen. When asked what the first thing he was going to do when he was an American, he told the Las Vegas Review-Journal "Collect unemployment."