Canon's PowerShot S90 had a lot going for it when it was announced a few years ago. It was small, powerful, and provided a nice bridge between the flagship G-series and the rest of the PowerShot line. The S95 came a year later, bringing with it only minor updates, including HD video and a new body coating, which made it easier to hold. But now the S100 is upon us. It looks different than those that came before it, and the guts have gotten a serious overhaul.