That applies for the games developed today. Do you think that line will change to
- Xbox 360/PS3: 1080p (some 720p/1080i games)
for games developed in 2010-2011?
No, I don't imo.
Look at how many games are running at 60fps at 720p, and then compare the number of games with dropped frames, tearing, etc at 720p.
There are always tradeoffs, and some games do better at higher resolutions, but in general moving from 720p30 to 1080p30 means you need to devote ~2x as much performance to your bottleneck at 720p. Which means you either need to cut quality or use a new technique (and typically you target a resolution so there will be many features that need to be changed in regards to quality or technique). If you are hitting the wall on Shader, Pixel Fillrate, and Texel Fillrate you are going to have to find ways to cut these down to move up to 1080p.
So the question is: What has the best final image on screen?
Resolution is not the end all be all of graphics. Personally I would love it if the 720p baseline was even removed as a number of developers have noted they could do a lot more at a lower resolution.
IMO I would take 720p over 1080p if that ment less shadow aliasing (which takes a lot of performance to reduce). If 1080p results in more shadow aliasing (or reduction in other lighting and shadowing effects) I think it is a loss over 720p in most games (RTS and such is game dependant).
There are exceptions (e.g. a game like VT3 which is more confined), but I think the current consoles are pushed pretty hard at 720p as it is. I think most developers will try to crank out higher settings at 720p than lower settings at 1080p.