It's kind of hard to for me to say just how amazing I think Halcyon used to be. It catered to my every vice (well....except two--one of which was simply because there's no parking around there, and the other only because I didn't hang out there quite often enough): food, beer, coffee, records, furniture, art (but, as I say, not the other two...).
Stupendous record collection, great sandwiches, amazing beer selection (Chimay! Hennepin!), nice espresso, and the swankest used retro-mod-New Frontier-Barbarella furniture you could imagine. They had a couple of turntables, and DJs would do in-store mixes while you sip coffee, eat a bagel, or both. Imagine if Other Music still had a Boston store, and merged with Abodeon the Enormous Room, Zeitgeist and 1369.
So.
They've moved now, from funky Smith Street to becoming-funky Dumbo, and are focusing on records. But it's still the Hanging Gardens of DJ Culture. And Francis Harris, aka Adultnapper, does a weekly-ish mix of new stuff that comes into the store. Done live, in one take, they are universally brilliant. Glitchy, funky, deep and seamless. And they're all archived. There's a new, questionably-useful Flash interface for them all; or you can dig down a directory and find all the mp3s.
Relatedly, Tim found some great stuff and has been compiling some dope-ass mixset links of his own.
Go forth and be musical.