You get what you pay for, but you knew that. The higher end cameras are much harder to learn how to use, but once you get the hang of them they are easier to use than the lower end cameras.
The big difference is in the lens. If you can step up to where you get the automatic stabalization feature that is part of the lens, it will change your world! With this feature, ultrasonic motors in the lens react to small vibrations, and make it seem like the camera is on a tripod. No more worry about longer exposures. No more worry about higher zooms.
Differences in pixel count, ISO, HDR all pale in comparison. I have a powershot SD1000, a Rebel T3, and the 5D Mark III. I got the SD1000 for the high ISO. The Rebel T3 outperforms the SD1000 a great deal due to the lens stabalization.