Suggest you google reviews of each camera and look at professional reviews, there are some very good professional camera review sites. From the reviews I've read over the years Canons always do well. Panasonic and Casio generally do well. Cameras are like most most technology, cars, computers, audio systems, etc, what's best depends on your budget, how you'll use it, what's important to you.
Here are a couple I like but there are more.
http/www.dcresource.com/reviews/canon/powershot_sd630-review/ http/www.dp review.com/news/0602/06022109canonsd600.asp