The combination of live view and a large and tilting LCD screen is a powerful combination and one I am looking forward to. It makes working low a lot more comfortable, not to say drier. It makes working overhead possible. It's not uncommon to find that the camera is at eye level, but it's aiming down so you still need a step stool to see in the view finder.
Likewise, there are awkward positions like a low camera looking up that need a contortionist to access the viewfinder, or at least someone younger, thinner, fitter and more flexible than me (that includes a lot of people to be fair).
This could be the return of the waist level finder for a different view point and less obvious photographing.
Initial presentations of live view have not been perfect, but it's clear that things will improve - autofocus while using live view for example, blackouts when taking the picture so following a subject is problematic.
Live view brings live histogram, what about live zones. Anyone interested in checking focus anywhere within the image. With my tilt/shift lens, this would be immensely valuable. As it happens, I haven't used that lens on my 40D, but sure will when my main camera has live view.
There are comments on the net about increased noise when the sensor is allowed to run hot because of using live view but I haven't come across any actual test - how long and how much - would be good to know.
Spot metering in live view would be a treat, being able to set one or more 'spots', each with a + or - X next to them indicating where they are placed relative to each other and to middle gray.
Mind you, I'm still predicting the demise of the optical viewfinder entirely - it's just a matter of quality and responsiveness - once those issues are taken care of, SLR's won't be SLR's any more - no mirror, no blackout, no pentaprism, tilting viewfinder. It wouldn't take much. The resolution on my Panasonic FZ50 electronic view finder isn't bad so double the resolution in both width and height would be downright awesome (4X as many pixels). Panning would have to be better and blackout during exposure would have to be minimized - I don't see these as difficult to achieve.