Wow, there's a lot of misinformation in here...

1080p is not instantly better than any other resolution, in fact, the TV that just won HDTV of the year, and Product of the year, is a Pioneer Elite plasma that's 720p native...that's right...a 1366x768 (720p) plasma looks better than even other 1080p plasmas. What your eye will notice most is contrast, not resolution.

Your best picture will come from HD-DVD or blu ray (I won't get into the format debate), any regular DVD you upconvert will simply not have any of the detail that a true HD disc has, end of story.

Any HD show/movie/sports event you watch on TV will be broadcast in either 720p or 1080i, nothing will be broadcast in 1080p for quite some time, if at all. Reason being is that 1080p requires twice the bandwidth of 720p. There is no room for cable companies to put that much content to your home (unless it went true fiber to your set top box).

360 can output true 1080p, but only games that have been rendered that way, same goes with the PS3.

You can absolutely get an HD signal over component (red, green, blue) cables, and get 1080p over VGA. You can theoretically get 1080p over component cables, however that standard was never approved for 1080p, and thus manufacturers have not manufactured a unit that sends a 1080p singal on that output, but it can be done.

If you have a 1080p TV, you can more than likely feed it a 1080p, and a 1080i signal, and never notice the difference. All fixed pixel displays (LCD, plasma, DLP) display the image in progressive scan. When you feed the TV an interlaced (1080i) signal, the TV will do what's called a 3:2 pull down, basically converts it to 1080p. The reason you won't see a difference is that the 1080i signal is being deinterlaced by your TV, instead of your source. The 1080p signal is being deinterlaced by your source (if needed), so either way, your essentially getting the same information.

Plasma's hands down have the best image, it's been proven in more than one study. Plasma's handle motion better than any other technology at the moment. Plasma's have a 60,000 hr half life, not a 5,000 life span. Panasonic units actually have a 100,000 hr half life. If you do the math correctly, 60,000 hrs is over 20 years of watching it at 8 hrs a day.