You can think of HD just as a resolution. (like 1920*1080, etc).  You can watch it on any screen that can run at a high enough resolution be it a CRT monitor, LCD monitor, plama screen, rear projection tv, whatever.

To send high resolutions out quickly you need fancy cables.  This is usually HDMI or component cables.  The current xbox360 sends the high definition/high resolution picture out using component cables so any screen that works at high resolution and has plugs that take component cables will work.

That includes pretty much every plasma tv out there, any big screen lcd tv, and quite a lot of the high res LCD computer monitors do it too.  TVs vary in price massively so sure you can just check any tv shop for a plasma or high def lcd tv for prices.  If youre going down the computer monitor you can also use for HDTV/high def gaming Id prob pick up:

Dell Ultrasharp 2407WFP 24" widescreen LCD Flat Panel Monitor
~£570

I was using the same setup as RivKid until recently, I am now running via the VGA cable on a 42" 1280*1024(WS) Plasma

My only advise would be to make sure that you get a widescreen monitor with a native res that is supported by the 360: http://hardware.teamxbox.com/reviews/xbox-360/40/Xbox-360-VGA-HD-AV-Cable/p1/ (scroll down)

I was using the same setup as RivKid until recently, I am now running via the VGA cable on a 42" 1280*1024(WS) Plasma

My only advise would be to make sure that you get a widescreen monitor with a native res that is supported by the 360: http://hardware.teamxbox.com/reviews/xbox-360/40/Xbox-360-VGA-HD-AV-Cable/p1/ (scroll down)

Nice upgrade.

Actually youve mae me remember that I changed res from 1360 to 1280x1024 set the xbox to widescreen mode and let the monitor make it fit right. This is what gave me the best quality image.

I currently use my 21" widescreen TFT as my display for the 360 at the moment.  Sometime in the next few months I plan on buying one of these.  Confirmed support for 1080p over HDMI, Component and VGA.  3x HDMI, 1x Component, 1x VGA.

Partial review here.  M86 and M87 are only have different fascia, they are essentially the same screens.  I believe the same may go for the N87 too.

Just to confirm, any monitor capable of displaying and resolution 1280x1024 can display true HD 1080 content?

I thought it was only super special TVs that were 1080 capable.

Nowhere near.  1080 requires a 1920x1080 (surprisingly) resolution to be displayed in full.  Unless it downscales to 720.

ah yes! lol, 1024 != 1080! Doh!

Do many TFTs / graphics cards support  1920x1080 ?

24" and up widescreen tfts will, like the dell 2407fpw.  Im pretty sure most graphics cards do too, I have a 6800gt which works fine but obviously games run a lot slower than they did at 1280x1024!

Assuming the screen supports 1:1 pixel mapping otherwise it will stretch the picture vertically slightly.