The 18-55mm is a decent lens. It is what I am using right now, only because I can't afford what I really want right now. How much do you know about photography? Like are you shooting in any of the manual modes(such as AV, or TV, or even full manual)? Shhoting in auto is fine, and you'll get good shots, but once you learn how to shoot in manual mode, thats where things get real intersting. I started out with a Rebel XT, and now shoot with a 30D. I am in the process of trying to afford some L glass. I want the 70-200mm f4 USM IS lens, but the price tag is 1400 bucks. A good website for tips and info is POTN. It's a Canon users website, and has tons of info on it. POTN stand for Photos on the Net. Her's a link to it....
http://photography-on-the.net/forum/index.php? . The XSi is a great entry level camera, and should be a very good stepping stone into the DSLR world, as my XT was for me. I have heard nothing but good to great things about this lens,
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=149&modelid=11924, as a good walk around lens. Suposed to be one helluva sharp, clean lens. But it is about 5-600 bucks. And that would interfere with my big lens I want. But it will be the 2nd pc. of L glass I buy for sure. Right after this one,
http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=150&modelid=14260 . There are a few good books out there also. Now if you already know all about photography, then never mond any of my babbling HA HA HA.