Jacknife has an amazing collection of tapes, vinyl, and used gear like stereos and tape decks. The quality is top notch, and if you can't find something out on the floor, chances are they'll have it in the back. If you see Trevor, tell him I sent you.
One of my favorite things to do on weekends is to head to Grand Central Market for brunch, grab a few glasses of wine at the Oyster bar and then roam around downtown collecting pigeons.
Over the past few years the market has been modernized and has become a really trendy spot, but it still retains aspects of what it was like decades ago.
Some of my favorite stands are The Oyster Gourmet, Sarita's Pupuseria and the Belcampo Meat Co.
It's a cemetery, but the view from up here is stunning and you can see one of the most large scale epic paintings ever made by a human: The Crucifixion painting, by Polish artist Jan Styka. It's a must see.