Two winners here: Vintage Vinyl is the best place to buy used CDs, hands down. Their offerings, both at the flagship Delmar store and across the river in planet Granite (City), are so broad and varied that Vintage is the first place to stop if you're short on cash but long on musical desires. Unlike the majority of used-CD places stuffed to the gills with old copies of yesterday's flavor of the week (Britney's Oops, anyone? Howsabout some Green Day Dookie?), Vintage Vinyl's selection is so wide that one can waltz in and find heavenly surprises, the kind you can't believe someone would actually get rid of. You gotta go to the Record Exchange on Hampton for the best vinyl selection (The Vinyl Shack on Big Bend is also way up there), an old library converted into a workhorse of a store. What's best about the Hampton Exchange is the apparent balance of choices. It's all there for you: the dense, ridiculously expansive easy listening section; the hip-hop section, thick with DJ copies of every stupid funky 12-inch to come out in the past five years -- the city's best DJs seem to ditch their unwanted records here; a soundtrack section filled with both the duds (Urban Cowboy) and the winners (Midnight Cowboy); a great country section; a decent rock section. The Exchange is occasionally flawed in the pricing department because they stick too closely to the idiots in Goldmine magazine, the record-collector's bible, and you have to be careful to check condition (they're less discriminating than Vintage Vinyl or the Record Shack), but for sheer volume and adventure, the place is heaven on earth.