As far as I'm concerned the pizza in New York/New Jersey/Philadelphia is the best. But what about those of us living in other parts of the country?
I spent six years in the Kansas City area. I found that if you looked in the older areas of town you could find pretty good pizza. Best in Kansas City: d'Bronx, Waldo's, Original Pizza, and Villa Capri. It's a lot harder to find great pizza in Kansas City compared to New York, but you can find it if you really try.
But if you live in a small town in Nebraska or Kansas, far from a major metro area I think you're gonna be eating a lot of Little Caesar's and Pizza Hut. It's still good but it's not as good as real Italian pizza.
My favorite pizza places are in Detroit, where I spent most of my life. Dearborn Italian Bakery is the best. Buddy's a close second.
Now I live in Phoenix, where we have great pizza thanks to the transplanted New Yorkers who came here to get away from snow and brought real pizza with them. New York Pizza Department is my favorite here.
Honestly, I'm not into Chicago pizza but I will eat it and enjoy it. But I woudn't go out of my way to get it like I would a Buddy's or a Dearborn Italian Bakery. Every time I visit my family in Detroit I have to get some pizza at one of those places without fail.