The International House of Logorrhea is the sort of site I love, but don't really use effectively as intended - I'm not really good at looking for an alternate word in the midst of writing; it breaks my flow.
I do play with Thesaurus style reference while editing, but I'm still more likely to beat myself about the brain than to actually look words up.
But I am the kind of logophile who loves to read this type of reference.( I was a great dictionary reader starting as a kid. I really don't understand people who can just look up a single word without being led down a never ending path.) If I can cram them into my brain, I can use them that way.
Anyway, I thought I'd share this link, in case you are one of any category of word reference users.
It includes interesting glossary groupings, which I am hoping I might use during the my process, and it is a component of The Phrontistery, which has many other free word lists and unusual word related resources.