The March issue of DTM Magazine, a Japanese electronic music magazine, boasts 122 free VSTs. They do a good job breaking them down by 32/64-bit, plugin type, and OS. BUT! You need to know how to read Japanese. If you can do that, click on to the rest of the article.
DTM
The Cheap Guide to Making Music, Part 2: Free/Cheap Synths, Effects, Sounds!
In Part Two, you’ll get a lot of links to useful info about free (or very cheap) software synths, effects plugins, and a couple of good sources for low-cost batches of demos and samples. And the best free drum library ever. EVER!