I went the exact opposite way--20D first, then 18 months later the original 5D+24-105-L kit, and then this June a brand-new 2nd generation Rebel 350D in-box at the Kits bankruptcy sale for $200.
To me, the silver, very tiny Rebel looks like a consumer camera or a P&S camera--less-conspicuous than a beefy,big,grip-equipped 20D or 5D, and one heck of a lot lighter and more compact than the 20D or 5D bodies.
I dunno...the newer Rebel cameras seem to have a lot of nice features,and the compact size of the T1i is very attractive to me and I am sure many others. It seems like increasingly people are getting much more uptight about people shooting photos in public places,and I think the smaller, entry-level gear draws a lot less attention than any of the XXD or pro-body size Canon bodies.
This October, I went to a pumpkin patch thing with my wife and son,and saw a mom and her infant son in his stroller, and the mom was taking pics of her little boy in the pumpkin patch. She had a hairbrush in one hand,and he was dressed up really nicely. I had my 5D + 24-105L over my shoulder. I walked up to her and asked, "Would you like a picture of you and your son together?" She said, "Sure! What newspaper are you working for?" I then explained--no....I meant, "Would you like ME to snap a few photos of you and your son using YOUR camera, so you can have a picture of the two of you together?"
"Oh, that would be so great! I just assumed you were shooting for a newspaper..." she trailed off...
The big stuff is kind of obvious..the Rebel-sized stuff is almost invisible.