This si Chowhounds Standard Discussion #132. Predictable answers (approximately in order) are:
Z-Pizza has a good slice
There is no good New York style pizza in DC. You have to go to New York
Better go to AV before they close (if they haven't already). The white pizza is great
The best NY style pizza is from The Italian Store
(some local joint nobody more than four blocks away has ever heard of)
The Italian Store, but you have to ask for it well cooked and with less cheese
Yeah, you might want to refine that request a little. There have been a lot of DC pizza threads, like best NY-style, best by-the-slice, best deep-dish, best whatever. You'll also see specific threads on Pizza Paradiso, 2 Amys, and others. Do a search first and come back to read some general answers.....