They're good cameras but usually more expensive -- why restrict yourself to Canon ?
As for choosing one -- you should first work out budget, whether you are serious or just point and shoot etc, etc.
If you are a complete beginner, start with a secondhand point and shoot until you have more idea what you need.
Although I previously used Canon professional and vintage rangefinder 35mm cameras, my first digitals were gifts from friends who were upgrading. After about five of those I have a better idea of what to buy, when I get round to it.
If you already have Canon SLR lenses then I would stick with Canon, otherwise any of the major camera manufacturer's cameras would be good.
First figure out how much you are willing to spend. Then if you have a store near you that sells cameras, go there and test them out. Pick the one that has the features you want and feels good in your hands. SLR camera bodies come in all different sizes even among the same brand.
I would also suggest reading reviews about the cameras you are interested in. A good review website is DPreview.com. You could also check out Popphoto.com, which is Popular Photography's website.