What do the different resolutions for HDTV mean? I have seen 480i/p, 720i/p, 1080i/p (I can't remember which have i's and p's)...what does the i and p mean? I thought regular TV had 640X480 resolution so why is 480i/p there, or does it mean normal TV resolution? I will be looking for a projection HDTV in the somewhat near future, what types of features should I look for? I was looking at some standalone amps for the future and was wondering why they take an RCA connection from the pre/pro instead of digital connection?