The Canon Rebel XSi is my first digital SLR, and I've been using it for around three months now. I must admit I was a bit wary about getting a brand new camera, but I've always liked Canon cameras since I used an ELAN II back in high school. Two years ago I also bought a Canon SD600 and I was happy with it.
The sports fan: Whether you are a motorcycle or soccer fan, shooting something in fast motion will produce unwanted results if you don't have the right gadgets. To capture the motorcycle or the favorite player, consider getting a camera with a fast shutter speed, continuous drive mode and decent optical zoom capabilities.
Let's start with the battery life. The XSi's battery life is amazing. I could take more than 5000 pictures and the battery only went low twice. The Live View feature, contrary to what a lot of people think, is not a replacement for point and shoot.
What do you like taking photos of? Is the questions you need to ask yourself. If it makes it easier for you, it can be compared with finding out what your zodiac sign is. If you know which photographic sign is yours, finding a digital SLR is much easier.
As for image quality, I must say I've been successful in taking pictures both in studio and outdoor settings. When I was in the studio, I used tungsten lights on the subject set against a white background. The image quality was great; perfect skin tones and very little chromatic aberration around the edges.
Sports and action. While you probably don't consider yourself an action photographer, if you take photos of pets and kids on a regular basis then you are. Since they move fast and you can't keep them in one place to take their photo, this type of photography is what you have to do in many cases.
All in all, the Canon Rebel SLR camera is solid, feels sturdy, not too heavy nor too light, and it fits right in your hand. If you're looking for a great camera and you're not restricted by your budget, the XSi is the way to go.
The Rebel XSi may be a bit too pricey for some people's standards, but I say it's worth every single cent and you'll have the quality photos to prove it. If you don't mind waiting a bit more, you can wait for its price to go down so that you can spend the money on extra lenses or accessories instead.