The Nikon D3 and D300 are not going to be $1999 tho...
The D3 and D300 are not competing with the 40D, the 400d and 40d are entry level DSLR's they compete with the Nikon D40, D40x & D80.
You should be compairing the D300 and the D3 to the Eos 1d series all of which are a shit load more than $1999inc GST...
As for live view, I think it will be benificial to studio photographers. Taking them out from behind the camera and allowing them to have a more personal touch with their clients.
Its turns a photographer back into an artist. However that said, if you dont like it you dont have to use it. Its a selling feature that just might make the difference for some buyers.
I mean its better to have a feautre you are not going to use rather than not having it at all, otherwise the buyer might be turnedoff onthat model and buy an Olympus
BTW. The 40D can auto focus in live view mode... It also offer two different silent modes in live view mode for the Jame Bonds of the world...
To clairify on auto focus in live view, you need to press and hold the AE-on button for a second til you here the usual focused beep and then release, the shot will then be in focus.
I have to say that Canons system to do this is the fastest I have seen in the live view cameras and this puppy is only 2 grand... Thats impressive...