The slice pictured here is from the always reliable, and inexpensive, Vinny Vincenz. Not far away are two pizza places considered near nirvana by many pizza aficionados: Artichoke, whose signature pizza is a thick-crusted, spinach and artichoke-topped hearty meal. (It's also a to-go only place with almost zero ambiance). There's also a new Manhattan location for Brooklyn stalwart Motorino (349 East 12th Street), which offers up small and pricey pies. Across town is Co. Company, which people seem to just call "koh" -- a trendy and slick place to enjoy fantastic sit down pizza and good wine.
New York Magazine does a find job of rounding up the contenders here, although note that Una Pizza Neapolitana has closed. This list from Always Hungry is also full of good suggestions. To get the absolute latest on the city's pizza scene, consult the Slice blog.