Far too many. I sold a camera once. My husband bought me the upgraded Sony Mavica CD and it wasn't as good as the old 2mp I had but he had already sold it to afford the new one. After all I didn't need two cameras back then! Then the wife of the guy we sold it to, dropped it and destroyed it beyond fixin'. Boohoo. Since then, I've only sold one other camera and it was my first k10d. Since I had another one and bought a k20d, I had to let one of the k10d's go. I'm not THAT unreasonable.
Here is what I've collected over the years:
Panasonic FX-01
Panasonic LX1
Panasonic FZ30 (I had two, one I gave to my daughter in law)
FZ1v2 (we have two, one is my youngest son's)
FZ20 (I gave this to my sister to use, even though I bought her a new fz28, I won't see my fz20 back. It is duct taped together at this point. So sad, that is a great macro camera. Even with all the abuse it has apparently seen, it still take good photos)
Mavica CD400
Olympus 765
Add on lenses for these cameras:
tcon14b, tcon17, Nikon tc-e17ed
wcon08b, mcon35, nikon 4t,5t,6t, raynox DCR-250
and I'm sure I'm missing a few.
I get emotionally attached to my cameras. They have all served me well. Even the old Sony Mavica CD400 takes good photos. It is just sloooow as molasses and large. I haven't shot with it in years. I won't sell it though. It'll be an antique someday ya know.
But really, it isn't worth selling these days.
p.s. Oh and I still have my old 35mm Minolta X700 and a few lenses for it. How could I forget that great camera!