Dust and dirt have long been a minor hassle for SLR users. Dust and sand get in, you open the body and clean it out. Minor.
Not so for the dSLR. Sand from the Indiana Dunes is showing up on my lenses a month after our visit. It must also be on the sensor. How do you clean a dSLR? Simple cleaning can be done with exquisite care -- or you send it to a repair shop. Or you throw it out and buy a new camera.
Not good. The interchangeable lens doesn't work nearly as well in the dSLR era as it did in the film SLR era (fSLR). I think the ideal camera for most amateur dSLR users today is probably not an SLR, but a better, higher end version of the very popular wide-range image stabilized digital camera. I don't think the dust clearing features of the newer dSLR will suffice by itself.
What we need in addition to sensor self-cleaning is a mechanical body seal that activates on lens removal. Pushing the lens removal button would cause the seal to slide in place. Remove the lens, blow the seal and lens clear of dust, attach new lens. An automated mechanical seal combined with sensor self-cleaning could make the digital SLR almost as dirt/dust/sand resistant as the traditional film SLR.