Best pizza; IMO, is NYC...if you like NY style pizza, which is my favorite. I like foldable, floppy, greasy pizza.
I spent one trip in NYC just going to as many dollar slice joints as I could. Quality varies quite a bit as you could imagine, but then again, on average, NYC pizza is the best for me. And my philosophy is, if you can't make a good plain cheese pizza...get those ingredients right: sauce, cheese, and dough...then there is no topping or extras that can hide your inability to make a good pizza. San Francisco, for instance, couldn't find a good pizza to save your life; only about dumping toppings on a bad pizza there.
The notoriety is partly due to the
NYC water they make the dough out of.
Just like the best cheesesteaks are in Philly. Gotta have the Amoroso rolls.