[LeRoux Strydom]

As far as dSLR's are concerned, the market leaders Canon and Nikon will continue to dominate other smaller players. The smaller producers may have innovative concepts and even adopt other standards, but the typical investment any pro or serious amateur will make in good glass will prevent them from jumping quickly to another brand. This is where te strength of Canon and Nikon lies. 80% of my investment is in good pro lenses. Bodies are disposable.

I think that APS sensors on DX bodies are here to stay. With 12MP now being the standard (shortly to be 14MP), no amateur can say that he needs more MP to print his 5x7 holiday pics. Canon and Nikon sell far more entry-level DX dSLR's with APS sensors than FF pro bodies. Thus there will be DX lenses and APS sensors for quite some time. FF sensors will be offered on the real pro bodies because pros need the high-ISO performance and the 20-24MP sensors to print billboards.

Also do not forget the advantages of the crop factor that you get on the APS sensors, it saves you from buying an expensive 600mm lens for your FF body when you can get the same field-of-view on a DX body with a 400mm lens.

I don't know about Canon, but the new Nikon D3 is compatible with DX lenses, the sensor automatically crops to APS and you're left with a 5 or 6 MP picture which is plenty, as you should know with your D70.

All in all, Canon and Nikon (even more so) are primarily optics companies. Their top-notch glass will continue to give them the edge over other market players. Nikon even outsources their sensor design and production to Sony.

I don't know much about 4/3 or other formats, sorry.