I just want to start by saying that - according to me - there are two types of pizza:
One is the NY style, by-the-slice type of pizza that should have a place on any pizza lover's list of places to go for a quick fix. In Leesburg, I would vote for Giovanni's.
The other is the gourmet version of pizza. The kind that will have multiple variations and will actually require a menu, that will be made by a chef. For this type, the clear winner in Loudoun County is Fireworks.
The question is: which do you want? There are times when I feel a little less sophisticated, and I just want to have a slice of pizza and a beer (maybe even a root beer). Then there are times when I want a pizza that goes with that great bottle of wine I just picked up. Good thing that Leesburg has a winner in both categories.
I will note that after it's success in Leesburg, another Fireworks restaurant was opened in Arlington. It is always just as packed as the original - a testament to how good this place is.