Best used/vintage furniture store in the city, hands down. Simply, their prices are actually reasonable! This means their turnover of items is extremely high, so you need to check in and check in often. They update their website frequently, but chances are if you see something you like online, it'll be gone before you even get down to the store.
Over the past few months, I've bought a great steamer trunk, my desk, and my kitchen chairs all from GUFF - needless to say, my place looks pretty fuckin' great.