The XT is amazing. The battery comes partly charged so you can immedietly start using the camera (thank you Canon!) I've already shot about 200 pictures with it and the battery hasn't died yet.

I can't give you a comparison between the XT and the 20D as I haven't owned a 20D, I can tell you a few things you may wish to know before buying.

This camera, is TINY. Extremely tiny. I'm a woman in my early twenties and I have small hands. The camera fits just right in my hands, but honestly, I don't see how someone with bigger hands would be 100% comfortable holding this. If my hands were any larger, they would be slipping off the bottom.
I had tried holding a 20D at a camera shop once and it felt too large in my hands to grip. The camera size is perfect for me, but just beware if you have larger hands. You may want to look into the battery grip, or test out holding the camera at a store before you order it. See the picture I uploaded above to get a size relation and how the camera fits in my hands.

For anyone who is migrating to this camera from a standard point and shoot digital camera, you cannot frame the image you are about to take using the LCD screen on the back. You must look through the viewfinder. The LCD screen is soley for menu use and preview mode after the picture has been taken, nothing more.

Something I've noticed is the camera makes a ratteling sound when moved around. I couldn't figure out what the heck it was, and then I finally reazlized it's the hinges from the pop up flash. It sounds like they are loose when the flash is closed. I went to Best Buy and looked at their display model, and yep, it has the same problem. Well, it's not really a *problem* but frankly something ratteling around like that sounds cheaply made to me. My Canon film SLR doesn't make that sound.
I use a 420EX Speedlite flash with my SLRs so the popup flash doesn't concern me, but it was something I noticed and thought I would share.

I love that Canon gave the option to have a black finish over a silver one.

The startup time is instantaneous which is absolutely wonderful.

The burst mode is excellent with 3 fps.

It's extremely quiet.

The image quality is excellent. You can get photo quality prints at 20x30, and even then I bet you could push it further.

I really can't elaborate more then what other reviews have said. If you are looking for a step into the digital SLR world, this is the ticket. Or you can even check out the newly reduced original Digital Rebel, but for the extra hundred bucks or so, I would just get the XT. You will not be sorry.

Two upgrades I would make right away: Get a Speedlite flash and the Canon 28 135mm lens.

Also, I don't know why people are submitting bad reviews grading Amazon on shipping for the Rebel XT. When I preordered the XT from Amazon (not from another 3rd party), it said it would be released March 20th. I got my Rebel XT in the mail yesterday (the 22nd) which if you ask me, is pretty darn good. Want something right away? Then walk into a store and buy it instead of ordering from the internet.