My two cents - I read the list of the accessories you would plan on getting with the S3IS. If you are going to get all that, why not get a dSLR? The main advantage to a fixed lens camera is weight and ease of not carrying lots of extra stuff. When I decided that I couldn't get along with an FZ30, I looked at the R1, but knew I wanted a longer tele lens than it has. By the time I got an add-on TC for it, along with the adaptor etc. I might as well be carrying a dSLR. The dSLR can do more things in the long run, and it can grow with you as you develop as a photographer.
I'm another one who LOVES the SR!