Which is better: 720 resolution or 1080 resolution?

1080 is the best. Lcd And plasma..its not which is better, it depends on the room your putting it in. If the room is going to receive alot of light, you wont be able to have a plasma. You wont see the screen clearly, there good for darker rooms or rooms with not as many windows. If the room has a lot of light LCD is the way to go.

1080 is generally better then 720. And yes 1080p is better then 1080i.

Here's a form of visual representation, found on Wikipedia...

http://en.wikipedia.org/wiki/HDTV#TV_resolution

Those numbers are generally supposed to refer to a screens vertical resolution.. i.e. 720 would be HD video that's 720 by 1280. But BEWARE the marketing and misconception. If you want to be SURE of a TVs actual resolution, look for a something that lists the TVs "Native Resolution". For instance.. you'd think a 1080i screen would have a vertical resolution of 1080 (1080x1920) interlaced... but in fact some/most are 1366×768, 1280×1080, 1024×768.... etc. Only the higher end 1080p screens tend to be full 1080 HD which is 1920×1080. Regular non-HD.. fyi... is 720x480 is the US/NorthAmerica/Japan and 720×576 in Europe.

LCD vs Plasma can depend on personal preference and/or need. Generally, the differences between LCD and Plasma and reduced considerably over the last couple years. But in short....

Plasmas generally have had better contrast ratios and better viewing angles. Because of often having better contrast ratios, among other things, Plasmas have been known for producing a better picture; though now adays there are some LCDs that can do just as well. Plasmas also have a harder glass screen that I believe can be repaired/replaced if damaged... so if you have little'uns running around that get their palms on the screen.. maybe Plasmas a good option for that as well.

However, LCDs suffer from "burn-in" considerably less... whichis one reason they're prefer by video gamers. Burn-in is a "ghost image" of sorts on a screen that can appear when the same still image stays on a screen for an overly extended (hours) period of time. This is why computer monitors have screen savers. Older plasmas had really bad burn-in problems, but newer ones have taken many steps to reduce this. If your careful with your TV however, and don't leave the same thing on for long (which included leaving something with bars, like a 4:3 image on for too long) then this shouldn't be a issue. Generally however, I suppose it's true you need to worry about how you use LCD screen alot less (although still some). Plasmas can sometimes have more of a glare issue then LCD.. though newer Plasmas come with anti-glare coatings... so they're not as bad.. but be careful when cleaning.

1080p is better than 720p or 1080i

1080i is better than 720p

720p is the minimum for HDTV

Plasma versus LCD is personal preference so I will offer no opinion any more on this subject.

1080, this means there are 1080 colours