Resolution is not as important as you might think.The most important aspect of picture quality is contrast ratio, the second is color saturation, and the third is color accuracy. Resolution actually is only a distant fourth!
Unless you have a very large television(50 inch or greater) and excellent source material, you'll have a hard time telling the difference between any of the HDTV resolutions.The leap from normal TV to HDTV is so huge that additional leaps in resolution--from high-def(720p) to higher-def(1080p) are tiny by comparison.Anyway there aren't too many full HD contents available.To fully enjoy 1080p content you need to have tv with screen size>50 inch and blu ray movies.
Also note that SD will look absolutely ugly on 1080p panel.(i have a dell 1080p panel and tata sky looks like crap).Well SD will look bad even on a 720p panel.Any HDTV will act like a magnifying glass, enhancing the imperfections which are specific to SD content.
So don't worry too much abt. resolution.As long as it is HD it will be great.Go buy a plasma that has better picture quality.
Could tell you which one to go for if you tell us the purpose of your purchase.What will you be using it for????