One thing to remember, as far as how big an electronics company is, Sony is bigger than Canon, Olympus, and Nikon put together. Sony manufactures many of Nikons sensors. They have done several things that both Nikon and Canon have deemed impossible.

I own and use all three brands. Sony has not yet come out with a truly "pro" camera, but has been in the point and shoot camera business for awhile. Canons USA representative has admitted that Sony is their main competitor in the point and shoot venue.

Sony is set to introduce a 24.6 migapixel "pro" camera this year. They have already introduced three excellent "prosumer" cameras this year, {four if you include the "semi pro" A700}. They have the only Zeiss auto focus lenses for DSLR available, {five of them}. My experience with Zeiss lenses is that they are absolutely excellent. There are litterly millions of used Minolta lenses on the market that work fine on the Sony cameras. When Sony announces something is going to be available, it is. No hedging.

From my experience with ordering parts from them, they are twice as responsive, twice as efficient, twice as easy to deal with then either Canon or Nikon.

If you look at Sony's effort in the DSLR business, it is nothing short of amazing.

I don't work for or have any connection with Sony. I just call'em like I see'um.

You have taken the first step towards making an informed decision. I just think it would be a mistake to not include Sony in your evaluations.