I'd call my downsizing style slow and meticulous. Slow anyway! It takes me a while to convince myself that I will be happier without certain categories of things and then another while to decide which of my things belong in those categories (such as books I'll probably never re-read or lend).
@rePete, check out bigwords.com - they'll show you offers from many bookstores. Note that most have a minimum they'll accept (because of the free shipping) and some give a little less than shown on the review if you want cash rather than credit. I ended up using Amazon (who gives only Amazon credit rather than cash) and eCampus (no minimum). You could also try donating them to college libraries.
I've also sold books and records at a used book store, but mostly I donate books to libraries and other things to GoodWill. Even using bigwords (much easier than eBay, etc.), it's kind of a pain to get the packaging materials together.