Thanks again for all the replies guys, I remember this forum was incredibly helpful when I was shooting a lot in college and you guys come through again.
I think I'm going to "demo" a 50D against a 5D and pick one. The 7D is too expensive and the 1 series is too much camera for me (and to lug around). My gut feeling is that I may end up with a 5D and a new wide zoom.
I really want to see a large boost in image quality, don't really need the speed.
The 40D is a much easier camera to use in virtually every respect..... both give great A3 prints.....but I feet the prints from the 10D have a better 'quality'.....hard to explain but a definite difference.
Personally....my next DSLR will be FF.....possibly the 5D if the price is right. I an happy with the 10MB images from the 40D......so the slightly higher file size of the 5D plus the FF should be a good value for money option.
I made the transition from 10D to 5D last summer (Amazon cc promotion to bring the new price down to $1667 shipped) and am really glad I went with full-frame. As the previous posters noted, you can get the 5D used for about $1100-1300. There's nothing wrong with the AF, and I heard from 7D users that they have some issues with AF. I did look into the 7D as a second body when it came out because of the better viewfinder and screen, HD video, and reach for sports.
Switching to full-frame also changed my selection of lenses and convinced me to try a couple new ones due to the difference in resolution and depth of field. With the 10D, I used to use 17-40 for indoor (usually with flash) and landscape, 50mm f/1.8 for portraits, 100mm macro and 70-200 f/4 (sometimes with 1.4x II) for outdoor sports. After getting my 5D, I bought a 24 f/1.4 mk1, 85 f/1.8, 100 macro IS, and played with a 135 f/2 but have been mostly using 24L and 100 macro IS. Since i used to use the wide end of the 17-40 on a crop sensor, the 24 f/1.4 covers the same fov on full-frame as well as handles low-light shooting. The 100 macro IS has narrow enough depth of field for portraits, and is great as a macro lens as well. The 50mm will also fit in my bag to fill out the hole if I think I will need it.
Good luck whatever you decide on -- I'll probably wait for the 5D mk3.
