Hi. I currently only own a Sony DSC W7 (it is a decent point and shoot camera, but isn't giving me what I want), but I am going to make the plunge and purchase the new Canon Digital Rebel XTi within a month or two. I am really new when it comes to SLRs and would greatly appreciate any pointers that you guys could give me. I am really in the dark when it comes to lens purchasing. I enjoy nature and would love to shoot wildlife photos, but I am unsure of what mm lens to buy, and is the IS really necessary if I am shooting from a tripod? Also, what kind of range could I expect to get with say a 70-200mm lens or the 100-300mm lens? Any information/help would be greatly appreciated. Thanks in advance.