Hello and welcome to the Cameralabs forums!
Yes, we are halfway through our 24-105mm with the 400D / XTi review! But we used the 24-105mm to test the 40D, so there's lots of samples with it throughout our review - check out our Gallery here
http://www.cameralabs.com/reviews/Canon ... ages.shtml
It's a superb lens to go for so long as it's wide enough for you on the 40D.
If you want a more general purpose wider lens, then the EF-S 17-85mm is a great choice, but it won't work on a full-frame body if you upgrade in the future. See:
http://www.cameralabs.com/features/Cano ... s_upgrade/