Deal on a 20D !!

[robodad]

http://portland.craigslist.org/mlt/pho/2123256256.html

[CastleRocker]

What is the difference between the 20 and the 40 or 50D's?  Is it just he size of the sensor, mp's, and the screen?  My daughter has been using my 50D and now she want's a camera for Christmas.  I've been looking at a couple other 50D's on Craigslist.  Man those things go quick if they are priced right!