Since Matt Groening hails from Portland, Oregon, he named several characters on the Simpsons after streets in Portland. Almost all of these streets are in Northwest Portland.
- Ned Flanders, after Flanders Street
- Rev. Lovejoy, after Lovejoy Street
- Mayor Quimby, after Quimby Street
Since the streets in Northwest Portland are all arranged alphabetically, these streets are all within a few blocks of each other.
In addition, further south in Portland is an area called The Terwilliger Curves, from which Sideshow Bob Terwilliger derives his name.
The connection between the characters names' and the streets is a little vague--- the Terwilliger Curves are known for being a rather treacherous and dangerous place to drive, and Sideshow Bob is. of course, treacherous and dangerous. Flanders Street has always seemed vaguely wholesome to me, but I only spent time there after having watched The Simpsons. As for the other names, I don't think they were meant to suggest the characters of their streets'.
2013 Update: Matt Groening has stated the (somewhat obvious fact) that as an Oregonian, Springfield, Oregon was the inspiration for Springfield. Of course, as a fictional locale with an unlinear history, Springfield is not "in" Oregon, but Springfield, Oregon is as close as a guess as any.