Geez, it would almost be easier to list what I HAVEN'T bought off of ebay.

Here are some examples.

-- Convention displays (two, actually, both 10x10 popups)
-- The wacky ergononic keyboard I am typing on and wouldn't trade for anything
-- My VCR, receiver, speakers, and DVD player
-- More computer parts than I can count
-- Massage chair
-- A bunch of DJ equipment for a friend
-- Various video, audio, editing, equipment

To answer jIgG, there's a certain amount of trust involved, but it's backed by Ebay's feedback system... users rate each transaction, so you have a reasonable idea who is likely to be trutstworthy. In 150+ transactions since 1998, I've never been burned, but I may just be lucky.