Interesting discussion, with the usual amount of one side of the coin or other comments.
I'm gonna garner the wrath of just about all on this site by speaking heresy -
I speak of the Fuji X-Pro 1.
Yes, I've invested in this little pocket marvel - and what a joy it is to behold. It brings back all the joy that the Canon A1's used to bring in the days of film (mid 1980's for me) - but with all the benefits of a mirror-less digital system.
To me, when you talk about mirror-less cameras, this is the current bench mark. Not because of its lovely retro styling or it's wonderful film emulation modes, but because of the quality of the build, the IQ, the low noise ISO, the ability to shoot colour RAW and B&W jpg side by side. Even the simple cable release for bulb or long exposure shots beats the hell off these modern computers on a cable just to press a shutter button.
It has its short comings compared with the upper end DSLR's when it comes to shooting action, but so do Hassalblads. The simple fact is - with the X-Pro 1, the future is here, the future is now.
It is for the likes of Canon, Nikon et al to start making the change.
For the purists, anything without a mirror will never be considered photography - but I thought that about anything that didn't require a roll of 24 or 36 slotted in at the back and sent off for developing.
In the way film is almost consigned to history, so will be the mirror in DSLR's.
I'm not saying this will happen at Photokina, but it will happen quicker than some people think.
Ultimately though - you should take your camera's out and actually take some pictures - that's how you'll best define yourself as a photographer