Having had a chance to use the 30D, 40D and XTi I personally would not choose either the 20D (obsolete) or 30D (still available-$980 with the 18-55 kit lens) over the XTi. I'll soon have a 40D but I won't be letting the XTi go. The XTi with kit lens at B&H is $589 while the 40D body alone is $1299. That's a major price jump even for the 30D. If you did opt for a 30D over the XTi there are a ton of used 30D's available at the moment. It's always a good idea to go to a local shop or Best Buy and play with each before buying.
