I usually avoid eBay anymore for camera gear, with all the shady sellers and misadvertised parts, unless it's high dollar and obviously posted by a personal seller and not a business. (These people are usually middle class to rich, take care of the gear, and are honest and won't rip you off.) I've been ripped off at least three times on eBay, just with camera gear - once, getting a "new" camera, fresh with three blazingly hot pixels, that turned out to be a pawn, and receiving a broken camera and not being able to do anything about it - old camera, not under warranty. My 50mm f/1.8 EF that I got from eBay has had a focus switch problem since day one.
Back when 300Ds were going for something like $650 on eBay (~4-4.5 years ago?), I landed a deal on mine - $425, with three batteries and a 512mb CF card. It looked just about brand new when I got it and I still use it as a backup body to this day.
Also got a good eBay deal on a Manfrotto tripod, ball head and pan tilt head in one auction... something like $90 shipped (even used, the gear I got usually goes for at least $150-200). It seems the amount of deals equals the amount of disappointment...
I recently got my A720IS, a Canon refurb as sold by Adorama, but as described in another post, the IS unit was malfunctioning right out of the box. I am waiting for repair / replacement.
With cameras, I've had the best luck buying new, from places with good reputations. I've only bought two high dollar refurbs, and both have been excellent. Low dollar refurbs have been hit or miss. I got my 40D brand new from Beach Camera, and my 24-105 f/4L IS refurbished from Adorama. Both have been absolutely excellent so far.
Now, as for my favorite? Whichever one is honest, and gives me a good deal. In other words, it doesn't exist