Most are good. If I had to pick one, I'd follow @Theodorekent 's lead and go with New York style.
One thing is certain though: The absolute WORST pizza style I've encountered - and I've lived all across the country - is St. Louis style. It isn't the thin crust or cutting it into square pieces or any particular topping choice that makes it horrible. Rather it's the horrid choice of - I hesitate to even call it this - cheese they use around here: Provel
No not Provolone, Provel. How does one describe it... It's a white cheese with a consistency only slightly firmer than Velveeta, and when heated it turns into a greasy cheese-like muck with the mouth feel of molten plastic. It's fucking disgusting - and they lap this crap up like crazy around these parts. Not a fan. The best way to eat a St. Louis style pizza is to refrigerate it and have it cold - the cheese firms up and it is almost palatable that way.
Here is what wikipedia has to say on the subject:
Provel is a white processed cheese prominent in St. Louis cuisine. A combination of cheddar, Swiss, provolone, and liquid smoke, Provel has a low melting point, a gooey texture, and a buttery flavor.
I rest my case.