I have the Rebel XT with several lenses that I am pleased with. I totally recommend the 50 mm 1.8, which is light, superfast and cheap and under $100. I also have the macro 50mm 2.5, which is nice for both soft portraits and macros of flowers, bugs, etc. I also have the 85 1.8 for indoor concerts or school plays that allows me to shoot low light with no flash. I also totally love my Tokina 12-24, which allows for awesome wide angle shots at only about $500. Finally, I love my Lensbaby, which gives you that cool Holga look for more artsy photographs. I bought the LBO, which gives a more dreamy look than the LB2. But everyone has their own preferences.
For more information, check out
www.lensbabies.comAnother super site for lens reviews and recommendations is
www.fredmiranda.com