I have a Canon G7 camera. What would I get from a Canon Rebel SLR camera that I don't have right now?

There are many differences. The main difference is the viewfinder: In an SLR you are seeing the actual image that will go to the sensor. It is diverted from the sensor by a mirror that flips up at the instant of the picture.

You also get interchangable lenses. You can buy additional lenses to expand its capabilities, such as a longer telephoto lens, or a macro lens for extreme closeup pictures. But your G7 already goes very close, and its zoom lens is 35 to 210 (35mm equivalent).

The kit lens on the Rebel is 28 to 88 mm (35mm equivalent). So you get less telephoto, but a wider view on the wide end. It does not focus as close.

The shutter on the Rebel 1000 goes 30-1/4000 second, and the G7 goes 15-1/2500 second. Another feature on the Rebel is Raw mode. The raw picture sensor data is recorded with no compression, and you can almost retake the picture on the computer.

Quality is great. The size of the image sensor is 5 X 7MM on the G7, and 14 X 22MM on the Rebel. The difference mostly shows up at low light.

The larger pixels can absorb more photons, and give less noise in the image. Notice that there are several Rebel models. It is a sub-brand for their "prosumer" line.

All have negatives that must influence your decision: cost and weight. An SLR is much heavier than your G7, and with extra lenses, even more. Changing lenses often lets dust into the camera, and that leaves spots in your pictures.

The answer to your basic question depends on what you feel limited by on your G7. Is there something you can't do? Check the features of the Rebel to see if it can overcome any shortcomings of the G7.