I recently bought a 42 inch samsung 720p plasma TV for the bedroom cause it was on sale quite cheap. I figured it will go nicely as a backup for my 67 inch 1080p.
There is no fucking difference between the two resolutions on most console games, unless you are sitting 2 inches away form the TV and you can see the actual pixels up close. Even when that close, its such a minor thing...
PC games is a different story.