Once you get a handle on the process you are most interested in (BIAB for example), I have found goodies on Craigslist from folks who went into homebrewing and lost interest for some reason or another. I found a Blichmann 20G kettle on CL for one half of the selling price....and the kettle was still in the unopened box.
I'm not suggesting you'll find the bulk of your equipment on CL, but its good to keep your eyes open for super deals. Also this site has a section for items being offered for sale.