The K20D is equipped with Pentax's moving-sensor image stabilisation system, which has shown itself to be one of the best on the market. Pentax claims that it offers four stops of extra shooting stability, but this is a little optimistic. Using the kit 18-55mm lens supplied, at the longest focal length of 55mm, conventional wisdom says that you need a shutter speed of at least 1/60th of a second for hand-held shooting, so adding four stops to this would give a shutter speeds of 1/8th of a second, but shots taken at this speed show very visible movement blur. Speeding up by one stop to 1/15th of a second produces shake-free shots fairly reliably, which is a three-stop advantage. It may be that the shake reduction works better using lenses with a longer focal length, but with the standard three stops is the limit. Mind you three stops isn't at all bad, and compares well with the performance of lens-based IS systems used by other manufacturers.
Dynamic range enhancement is becoming a must-have feature on high-spec digital cameras, and especially on DSLRs. All the main manufacturers include something of this type; Sony has it's DRO system, Nikon has Active D-Lighting, and so on. Naturally Pentax has such a system, called Expanded Dynamic Range, which is activated from the ISO setting menu. It is pretty straightforward, simply selectively altering the sensitivity to enhance shadow detail and reduce highlight clipping. As such systems go it is very effective and has no noticeable negative impact on image quality.
The other essential feature for any modern DSLR is monitor live view. The K20D has this feature too, although like the EOS 40D it is a bit limited. It doubles as a stop-down preview, so the image will be very dark at narrow apertures, and of course autofocus is not available while in live view mode. Still, it is a useful feature under some circumstances despite its limitations.