Very few game will be rendering at a native 1920x1080, if they are then there not going to be doing much. If any game is going to render at 1080 on the ps3 then it will be doing 960x1080 this is to get around the fact that the ps3's internal scaler is a pile of rubbish that can't scale 720 to 1080i properly. On both consoles your better of just setting the output to 720p.

Dojj, as to the ps3 shaming the xbox when it comes to high end graphics just stick with your 360 unless you fancy a cheap blu ray player.