Overall, the Rebel XTi is a very nice upgrade over XT, but not a humongous upgrade. Some of the improvements are as shown above. The camera still feels a little small, but the grip has been improved and if you add the battery grip, it feels like a new camera. The self cleaning unit shakes the low pass filter in front of the sensor to rid it of dust. This self cleaning unit has been questioned by many but the bottom line is that it is better to have than not have. The 2.5" LCD is very nice and has all of the camera settings displayed on it since there is no top LCD. The 10 megapixels is also another nice upgrade. This camera is relatively cheap and is a great buy.
Hope this helps!