Xsi or XT1i for on-the-go Canon camera?

I have a Canon 40D, and although I love the picture quality and the camera in general, it is just too bulky for most of the things I do, and so I end up leaving it behind often. Also, I have a bad wrist and have trouble hand-holding such a heavy camera. Although I mostly practice landscape photography (tripod-mounted), I end up taking a lot of photos 'on-the'fly', and so I am thinking of selling the 40 D body and picking up either an XSi or XT1i. (I have several Canon EFS lenses, so I need to get a Canon body). I know the bodies of these cameras are fairly flimsy, but I really do need to reduce the size/weight of the camera I'm lugging around.

Does anybody have any recommendations or experience with the XSi and XT1i? In the best of all worlds I want a camera that is as strong as the 40D, but as small as the XSi, and that takes great quality photos! (I could care less about video capability). Thanks for any input!

I've owned both cameras, let me know if you have any specific questions. As for image quality, it would be tough to tell the difference between the two. If you don't have any interest in HD video, the XSi might be a good choice with its exceptional value.

Thanks Justin - specific question: is the XT1i tougher? It looks like the casing may be better made, but perhaps not. Also, I have read about some auto-focus issues with the XSi... not focusing properly...

I have the XSi also the XTi, and find it to be very satisfactory for everything I do. As far as the body being tougher, I couldn't say since I have only used the Canon Rebels. However my cameras have gone to the Rockies, Olympic Nat. Park, many zoos, wildlife parks and nature centers, plus been out in cold and heat, and I have not had any problems with the construction. But, I have not had to fend off any charging bears with them! I also have problems with my arthritis, and hip and back, so the XSi works fine for me. Hope this helps.

Yikes, the Xsi is only $485 at Amazon. For that price, almost hard NOT to pick one up! Prices are getting amazing.

The T1i has a better feel to the grip, but I don't think that translates to being tougher. As for the XSi and autofocusing... never had a problem on my end and reviews for the XSi are off the charts solid. For the T1i as well. The rebels have really become an incredible featured line of camera!

I have an Xsi and I've never had a focusing issue. From what I read about the autofocus issue it was mostly people not knowing how to properly use a SLR--it was their first upgrade from a P&S.

Hey thanks a lot for all the input, much appreciated! Seeing that the T1i is more expensive and the main difference seems to be video capability, I'll probably o with the Xsi