I've had a 42 inch Toshiba HDTV with SKYHD for a while now.
However, there just isn't enough content being shown in HD at the mo. If it wasn't that SKy Sports was available in HD I wouldn't bother.
You want HD as Lilac say's at 1080i/P not 720i/P. If you read the link Lilac added you'll see the difference between i and P. Basically, i gives you a better picture quality, but P is better when movement (like Sports) is involved.
Second, if you are looking at a package, DO NOT get a HD DVD. That's High Defn not Hard Disk. Some players have a hard disk in to record onto (like in a Sky HD/Sky+ box). Anyway, the HD format DVD player has been pretty much killed off and I can see the electrical shops trying to sell them off cheap. You want either Blu Ray (disks are expensive) or an upscalling DVD, which scales up your current DVDs to almost HD format.
Now this isn't as good as a Blu Ray disk player, BUT it's a lot cheaper (mine cost me £65 AND it plays multi-region) and you won't have to replace all your DVDs. I remember watching Return of the SIth for the first time and drooling uncontrollably. Though that might have been the drugs 
Of course the Japanese are working on a Super HD format now....
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