Panasonic makes the panels for Pioneer (iirc) so basically if you're in the market for a Plasma (which you should be since they are superior to LCD) you can't go wrong with either of them. The only thing to watch for is Burn-in/Image retention, which in my experience has only happened with consoles that aren't PS3/360 and any static image.
What you want to look for is a high Contrast Ratio(CR), most manufactures now list CR as Dynamic Contrast Ratio(DCR). IIRC DCR is about 4x the real CR. (10,000:1 DCR is 2500:1 CR) After that you want a TV with the Blackest Blacks and the truest colors. Resolution is last in the technical aspect of deciding really.
I can't be arsed to look at specs and give my recommendation right now, but basically like I said if you're going Panasonic it will be good (I've(well parents really) got a 2yo 720p Panasonic and it's fantastic.) Pioneer is better but basically the same as Panasonic with improvements and a higher cost, also more bragging rights.