I'm reading the 'A year ago I only had... ' thread and it strikes me that most* of those who have replied have bought a camera in the last year.
I think if more info was added to the "A year ago thread" You could really tell if people where buying a new camera each year.
For me I had my 20D for almost 3 years now so when I get my 7D I probably wont buy another body for years to come. I will say I buy more lens or other equipment yearly but not a new camera body.
Now if your talking about my dad then thats another story ! My dad literally buys new cameras all the TIME. I lost count on how many he has " he is a electronic Hoarder" I think he had 3-4 Dslr and probably more point and shoots than I can count. I just went to sammy's to get him the T2i 2 weeks ago LOL