Un-

I just like the no-nonsense no-excuses attitude at Unfuck Your Habitat.  It's not totally my cup of tea, since I can already deal with straight up mess when I want too.  In fact, I'm probably a little too good at it - since I'm so good at hiding things, it's too easy to think I don't really have too much stuff.  But I do like the site's emphasis on dealing with specific, small, and/or manageable tasks, and that they are very functional goals, like making sure you are ready for work and can use your kitchen.

For advice on how to actually get rid of things, I go to Unclutterer, where there is a lot of emphasis on the emotional aspect of things.  For instance, there are a lot of articles and questions on how to deal with inherited items.  There is practical advice, too, like what items to avoid acquiring (site author Erin Doland calls these "Unitaskers,") but also what organizing tools can help you access/display the items you do retain.