[N54YO]

After shooting with my 40D it's hard not to be satisfy with it. I have an XT also and that thing is super tiny in comparison. I have battery grips on both models. I do appreciate the XT however when I just want a super light package to walk around with. The 40D is a completely different beast in term of performance. I have yet to experience the XSi so not sure how it would perform against the 40D. Good Luck man. Either way, be prepare to indulge in a satisfying hobby.