If memory serves, the HDX offers a number of improvements, including better CRTs and DVI input (for a future HDTV feed). The enclosure build quality is also improved.
If the nicer looking (subjective opinion) enclosure, and DVI input aren't important then save some money and get the 65H82.
On another note, if you're willing to wait 3 months or so then the 65H83 will be coming out, and that will surely drive down 65H82 prices further as it will become a clearance model. Or you can spring big coin for the 65H83 - it's supposed to have even more improvements for us feature hungry geek types
Sean.