from experience you probably won't tell the difference between 720 and 1080, I mean you can but I have a feeling that you won't miss it if you don't have it. The only time I've seen this become a serious issue is at these sizes at extremely close proximity to the TV, at which time the other imperfections (quantization and blocking) of the source material to me is MUCH more noticeable and distracting.

That is unless you need it for a computer monitor as well, at which point 1080 is probably the best choice.