The A720IS would be a good starter with the manual options available. Learning to use AV, P, and TV in a point and shoot will help out when you want to move onto an SLR. SLR's with kit lens and using auto modes usually disappoint people that buy them thinking it will make their pictures better.

Also, the camera is just a tool, and the better you become in understanding light and composition will make the biggest impact on your pictures. I like the lines you can add to the screens to help compose photos with the rule of thirds.