I'm sure there are many more people I'm forgetting. If you think of someone else you can add them. I couldn't imagine a person who doesn't like the Simpsons. I have yet to meet a person who didn't like the Simpsons. Not wanting your kids to watch the Simpsons really is the only acceptable reason for not wanting to watch the Simpsons.
http://www.ranker.com/list/simpsons-characters-who-seem-awfully-similar-to-real-people/stokified,
Rainier Wolfcastle
I'm going to go out on a limb and say that Arnold was the inspiration for Rainier. It's probably very controversial to say that.
Fat Tony
I'm really not sure if Gandolfini ever played a mafia boss before Fat Tony was ever introduced on the Simpsons. Gandolfini is still the most logical choice regardless of who Fat Tony was based off of.
Julius Hibbert
According to Simpsons Wikia Julius was based off of Bill Cosby. Makes sense to me.
Kent Brockman
The Simpsons Wikia page lists 9 potential inspirations for Kent Brockman. Jerry Dunphy was number 1 on the list, coincidence?
Joe Quimby
Okay Quimby looks nothing like JFK. You have to admit his entire character is spoofing JFK though (besides looks.)
Sideshow Bob
Kelsey Grammer does do the voice for sideshow Bob on the Simpsons. This is how I think Fox got Kelsey Grammer to commit to do that voice.
Fox: We've basically made up a character that was basically you combined with a psychotic serial killer on the Simpsons. Would you please do the voice?
Kelsey: I'm in, I love the Simpsons.
Capital City Goofball
I've never read anything that compared these 2. I'm sure someone has and it's pretty obvious.
Bleeding Gums Murphy
Apparently bleeding gums Murphy was based off of Sonny Rollins. I really wouldn't know, but the term loosely is brought up when comparing the 2.
Drederick Tatum
Drederick and Ranier are the 2 most obvious copied real people. While Ranier might hurt Schwarzenegger's image, Drederick probably helps Tyson's image. Drederick is actually a toned down version of Tyson.