The imac won't be where they introduce a revolutionary display. It'll either be in the macbook pro or in the cinema display. The imac is a consumer device, and as such, will be targetting 1080p resolutions, and whatever video standard is introduced later. As it is, most people wouldn't make use of the resolution already available on the 27" imac. It's a darn nice display, especially given the pricepoint of the imac.
I want a thunderbolt equipped macbook air 11" with a 21" imac at some point, tho...