I'd been planning to get an nVidia 7800 and the nVidia decoders, on the basis that the 7800 had an excellent press as an MPEG decoder right up to 1080p, and the nVidia decoders also have an excellent press and seem to do most things automatically without the user needing to know too much, and presumably they will work very well together.
However, I have just read this:
http://www.trustedreviews.com/article.aspx?art=2278
It sounds as if ATI have actually leapt ahead here, at least in hardware terms. However, I didn't notice anything in there to suggest ATI are actually providing a decoder in their Catalyst driver package, or whether you would (as in tha past) need to have one of your own.
Can anyone shed any light?