720p will look just fine on a 40" to 50" television. ANHR in 560p (is that right?) looks pretty good on my 42" LG LCD 1080p television.
Unless you sit really close to the screen (which is dumb) 720p will look amazing. Any way, Ady's source materials as Chainsaw stated didn't really need to be in 1080p in the first place. It would be as silly as converting an MP3 to FLAC.