OK, my first real post here on this forum: I just went through this process (D40x/XTi) and finally chose the XTi. I don't think anyone mentioned my reasons yet for selecting the canon.
1) Fit: Pick up both cameras and see how they feel - the canon has a smaller grip, but it works well for my hand size. I do know someone who liked everything about the Xti except the grip so he put on a battery grip and it fits his larger hands. See what feels good to you.
2) Size: My old film SLR (Nikon) and favorite lens are great, but heavy. This time I wanted portability. The xti is very light and smaller than some of the other cameras (put them side by side - you will be amazed at the difference!)
3) I'm a newbie to dSLR and the digital world is changing so quickly, I assumed that after a few years (and thousands of clicks) I may want to change bodies. At that point, I will know myself better and what/how I like to shoot. I could do a direct replacement or choose to step up to a better body - Canon has wide selection of bodies at various price/performance points.
Good luck and have fun!!!
, now have 400do;500f4is,600f4 

----Brad---- 
