bortz,
When I was vacationing in Massachusetts last year I spent some time with a local pizza operator who specializes in NY style pizzas. He uses a Baker's Pride deck oven that can get up to 550 degrees F (or so he said). He bakes his pizzas at 470 degrees F.
If you research pizza ovens, like Baker's Pride and Blodgett ovens, and look at the specs, you will see that the oven temperatures generally range from about 500-550 degrees F (even though the specs may list an outside max. temperature of around 650 degrees F). From what I have read, as a practical matter, most pizza operators tend to use 500-550 degrees F, and are happy to get a constant 525 degrees F temperature if they can (which is not always easy with the doors being frequently opened and closed.) However, it is also common for some pizza operators, like the one mentioned above, to use lower bake temperatures, say, around 450 degrees F. The actual bake temperature selected will depend not only on the type and model of oven, but the type of pizza to be made, whether the pizza has a thick or thin crust, whether pizza screens are used or not, etc.
Peter