The results are pretty much what I expected, people hit on a few of the big ones, a lot of people just basically "repped" their own region.
I like to answer questions using hard data but flexible definitions. There are a lot of different ways you could answer this, here are six that I could think of, and the data supporting each for 3-sport cities. 2-sport cities such as San Diego and New Orleans would rank very high (or low, depending on what you want to call it) in this analysis as neither of them has a championship, but who knows what could've happened if they had a 3rd.
The time frame is 1966-Present, because the Super Bowl as we know it today where there was really one football champion, rather than an NFL and AFL.