Jason points out the fact that cities have flags; you can see them all ranked in some survey here.
I had no idea at all that cities even had their own flags -- Buffalo's, at no. 32, is completely unfamiliar to me -- but on the basis of what I see here, how can Washington's rank first? That flag is freaking ugly. Actually, a lot of them are freaking ugly. Corpus Christi's is nice, though.