1080i,1080p, 780 etc.....what does this mean with tv's?

1080i 1080i means 1,080 horizontal lines are used to create your TV picture. The i stands for interlaced scanning which means the picture is formed on the screen by scanning in two consecutive passes where odd numbered lines are displayed in one pass, and the even numbered lines in the pass that follows. 1080p Also known as "Full HD", 1080p means 1,080 horizontal lines are used to create your TV picture — that’s a lot! The format is currently being used to produce Blu-ray discs, but not TV broadcasts. The p stands for progressive scanning, a technique that scans and displays all of the lines at the same time in one single pass on the screen. 720p 720p means 720 horizontal lines are used to create your TV picture. The p stands for progressive scanning, a technique that scans and displays all of the lines at the same time in one single pass on the screen. 720p is what the majority of broadcast high definition content is being transmitted in at this time. The difference between 720p and 1080p is the number of lines in the image, 720 lines versus 1080 lines. An image with 1080 lines will have a higher level of realism and definition than an image containing 1080. 720p and 1080i high definition televisions are available now at very reasonable prices. The same size television with 1080p capability will likely cost a bit more. If you are the kind of person that sees yourself keeping this new high definition television for the entire life of the unit then most people would suggest saving the extra cash and buying a 1080p set, especially if you intend to watch high definition DVD's on it. If, however you think you will trade up to a newer television in a few years then a 720p/1080i set would be fine.

These numbers refer to the screen's image resolution. 1080p (for progressive scan) will give you the sharpest picture, but unless the TV is bigger than 32", you probably can't tell the difference.

you might as well get a 1080P. It stands for 1080 lines of resolution with Progressive scan which means all lines refreshed on a frame at a time. 720 is just less lines of resolution. 1080i is the same amount of lines of resolution but only every other line is refreshed at a time. Theoretically, 1080 P is the best but it's probably not likely that your eye can tell a difference.