I had a hard time discerning detail differences b/w two 42" screens at Best Buy, a $3500 1080p Sony LCD and the 42" Panasonic (generously) 720p plasma. This was especially strange b/c I used to notice that 37-42" 720p LCDs seemed to show more detail/res in static shots than 42" plasmas back when I was comparing the two intently. My point being that, sure, screenshots look nicer at 1080p, but I'm interested in how apparent the extra detail will be on similar-size (but different res, natch) HDTVs.
Well it's essentially guaranteed that unless both displays were hooked up to a Blu-Ray/HD DVD player, you were looking at 720p content.