Can the market support so many US exchanges? (do any have working USD ?)
buttercoin (no selling yet? ACH? wire? CC?)
coinbase (technically not an exchange but USD works)
campbx (bank halted ACH/wire transfers on January 31, 2014)
kraken (located in SF, USD back soon: https://news.ycombinator.com/item?id=7321703 )
coinsetter (in beta, bank approved USD)
cryptsy (located in FL, USD soon, registered Money Services Business/BSA/FinCEN)
coinlab (never opened exchange)
coinmx (may not actually be in US, overseas CC charges, be careful)