Is there a huge difference between 720p or 1080p HDTV?

[facher83]

For the most part the information being presented in this thread is completely, utterly bogus and poorly informed.  720p is a simple comparison to a width resolution of 720.  1080p is 1080 width.  Due the math, you are talking about a similar comparison of 1024x768 monitor resolution and a 720x540 (making this up) resolution. 

An HDTV is a component device of a home entertainment system.  Will some people notice their optical audio, 5.1 sound on a VHS player?  No.  Infact, probably not at all.  If you don't use it, sure, you won't notice it.  If you are displaying a 1080p media, such as a any signal that is accurately sent in this fashion (not upscaled or downscaled) you will notice a difference period.

The upscaling or downscaling technology is also a HUGE factor in appearance.   I have a DLP projector and the correction on odd resolutions is unbelievable.  Instead of dropping pixels it conforms nearby pixels and very clearly downscales the image.  Most LCD displays, older ones at least, will drop pixels in downscaling a signal.  If you have the right technology downscaling, the image loss can actually work very well.

Interlaced signals and Progressive signals are different.  Some will notice the difference, some will not.  Most probably will.  Progressive -usually- shows a still image better, while interlaced probably shows moving images better.

 

Although the resolution debate is the kicker.  It's like comparing 7 mph to 10 mph.  You should notice.  The question is what are you needing it for?  Just make sure your downscaling is accurate and presents a good picture.