Oh man, I can't believe this place isn't on Yelp yet. There aren't enough good things to be said: this place defines Pittsburgh pizza, and remains the best I've ever had. That's after living in both Chicago and New York--I order a Vinnie pie every time I'm visiting the Burgh.
Vincent himself is a big, burly, old-school pizza-joint guy. There was usually a cigarette dangling from his lips while he tossed the dough, but that makes for character--growing up, there was always a dumb but entertaining rumor that the oven-blackened flour on the bottom of each pizza was ash from the cigarettes. They've had the same location for years, just between East Pittsburgh and Forest Hills. I think Vincent retired, but they still do things the same: enormous pizzas (if a bit expensive, but again, they're enormous) with cheese piled on top of a thick, slightly doughy (but in a good way) crust. The toppings are piled on even more thickly, especially the pepperoni (my favorite) which comes in meaty chunks instead of thin, round slices.
As soon as you get home and tear through the paper wrapper -- only the bottom half of the box here -- you're in for something awesome. Lots of people come here to eat in-house too, where the dark walls give it a cool, slightly seedy feeling similar to a pool hall. For some reason there's been a proliferation of other pizza places trying to steal some of Vincent's good name, but those places (PNC Park in particular) suck. Be sure you only go to this one. You won't regret it.