If weight/size is a concern, I would STRONGLY recommend the new Canon Rebel xSI (aka 450D, should be coming out soon, but the current/old models can be found cheap now). The functionality of the Rebel body is very similar, and in some ways better than the Canon 40D.

Oftentimes more important than the body is the lens, but the kit (included) lens for the Rebel (18-55mm with image stabilization) should be satisfactory for just starting out and learning the basics.

Nikon fans will of course steer you towards the Nikon equivalent of the Rebel. And to be fair, the Nikon equivalent would be fine as well.

My recommendation, if you're just starting, is to get the cheaper Canon Rebel XTi (just the body http://www.amazon.com/gp/product/B00...SIN=B000I1ZWRW) and get an all-around lens like the Tamron 28-300 w/ Image Stabilization http://www.amazon.com/Tamron-28-300m.../dp/B000V6ON8I

Allin only around $1100. If you hunt around you could probably knock off around $100-200 probably through different retailers, merchants, or ebay.