Photo from seattle-daily-photo.blogspot.com
There are a lot of good reasons to shower Bike Works with praise. The nonprofit bike shop does youth and adult education classes, kids' camps, mentoring, and an earn-a-bike program, and refurbishes donated bikes to resell at low cost---all on top of serving as a full-service bike repair shop.
That's all fantastic, to be sure, but my affection comes from a much shallower place. Bike Works has some amazing deals on bike parts.
I rode down to the shop yesterday afternoon to pick up parts for a project bike. Some of the sweet deals I walked away with: a slightly-scratched, but excellent-condition Shimano 600 rear derailleur (second to top-of-the-line in its day) for $5, perfect condition alloy drop bars for $5, and a set of unused MKS touring pedals with clips and straps for $25. I've gotten equally good deals each time I've visited Bike Works.
There are other shops that sell used parts, but few if any that can match Bike Works' volume. They've got large buckets of used parts out front to dig through. If they don't have what you need there, they've probably got it in the back or in their nearby warehouse. There are plenty of junky-to-so-so parts in the mix as well, so it helps to know something about bike parts and their quality levels to find the best deals. But the mechanics at the shop are very knowledgeable and ready to lend a hand (they also don't have that holier-than-thou attitude that plagues so many shops).
There is, of course, an elevated risk of finding too many good deals and spending way more than you had planned to. But at least you'll be contributing to a worthy cause.