The Canon PowerShot S5 IS has very impressive specifications. We'll see how well that thumbnail sized sensor does at higher ASA ratings, but this feels like the beginning of the end for the dSLR. Many pros will use this as a backup camera, and many prosumers who might have bought a dSLR will choose an S5 instead. Current prosumer dSLR owners will hold off on major lens purchases, anticipating a possible future switch to an S6, S7, etc.
The dSLR has always been, very obviously, a transitional technology. Mechanical prism? Sensor dust? Ummm, no. The only question was when. Now I'm thinking dSLR sales will start to decline by late 2008.