This is my list since I graduated high school. It doesn't include cameras belonging to my parents that I used nor does it include a box of assorted old cameras I have collected over the years. These are all cameras I have actually used, some of which I still have. (Dates approximate...)
Kodak Instamatic 110 - sold at yard sale
Rolleiflex - still have
HP C30 -sold at auction site
Olympus C-5050 - still have
Canon S45 - sold on auction site
Canon s230 - still have and use it for 640x480 video shots
Canon 1D - sold here on FM
Canon 10D - sold on auction site
Canon D30 - still have
Leica D-Lux 2 - traded here on FM
Canon 20D - still have and use daily
It seems that most (not all but most) of the people who have a long history in photography with many different cameras have "maxed out" (if you'll excuse the term) at the current top-of-the-range prosumer cameras. While the people who have risen to the pro cameras have done so quite quickly -- either quickly in time, or quickly in the low number of cameras they had beforehand.
I'm probably in the extreme minorty, having gone from no camera to a 1D in a matter of months, albeit after a decade-long desire to get into photography. But glancing through the thread there does seem to be a trend emerging.