Originally Posted by RWetmore
The 1080 signal standard is for horizontal lines, not vertical. Vertical is 1920.
You're confused about your terminology. Horizontal is from left to right. Wide screen HD is 1920 pixels wide (max). Vertical resolution is from top to bottom, and this is what the "480i, 540p, 720p, 1080i and 1080p" values designate.
A "perfect" quality HDTV for BR Disc or HD-DVD would have a minimum of 1920x1080 static pixel resolution, although double this would be better for scaling of 720p content (do the math).
CRT technology is a totally different story and I may post a longer comment on that later, but basically CRTs allow for resolution increases beyond their normal refresh bandwidth via interlacing. The reason you interlace is that the TV can't actually draw all the lines it has within the time frame for a full vertical refresh so it draws half of them, then the other half, alternating even and odd vertical lines for each refresh.
A CRT screen refreshing 60 times per second in interlaced mode at a given resolution will look essentially the same in picture quality as another CRT refreshing 30 times per second at the same vertical resolution because of how the phosphor coated pixels decay non-instantly. However, the 60fps interlaced screen will actually have smoother motion if the data its rendering really is 60fps interlaced since the "second" part (field) of each frame is not actually the other half of the frame, but another new frame that continues the motion.
This is why deinterlacing is so important on LCD/Plasma screens; they don't have the same visual science as CRTs and the interlacing causes wierd jaggies whereas on CRTs they look fine.