I am thinking about getting an HDTV for my PS3. I found a good one that is 1440x900 native resolution, but I have heard that the picture wouldn't look as good with a 720p signal, because the TV has to upscale it. Is this true? Would a 1366x768 native res TV look better with 720p?

A source should always look better when viewed at its native rez without any scaling taking place. But, a 720p source should look fine upscaled to 1080p as long as the tv has a good scaler.

I use a Pioneer 5070HD plasma 1366x768. The plasmas really do have a superior picture, but any hdtv will probably look great. The Panasonic is cheaper and very good.

The rez you were talking about must have been a smaller lcd screen. Was it a pc monitor? It will probably be fine, but I would suggest a plasma for the best possible picture. If a plasma is out of your price range, then I would suggest a RP 1080p, as big as you can afford.

Many threads on this in the display section but hard to find an unbiased answer.