Used Record Stores & Audio Gear in NYC

Hi I'll be visiting NYC at the end of the month. Staying at the Sheraton (I think). The hotel is beside/behind the site of the former World Trade Center.

Anyone in NYC know of a good used record store that I should check out. A large variety of music would be preferable. However, I primarily listen to and am looking for alternative rock (Beck, Red Hot Chili Peppers etc), American hardcore, old school hip hop (Tribe Called Quest, EPMD, Guru Jazzmatazz, Beastie Boys etc), Blues, and funk.

And of course, classic good ole rock and roll. But I can find those almost anywhere.

Are the record shops found in an "area" or are they spread out over the 5 boroughs.

As well, any must-go-to Audio stores. Mostly interested in used gear, especially analog and speakers.

I only have a day, so any help/suggestions would be greatly appreciated.

Thanks.