I started out with an HD-XA1, and then added a Panasonic BD10, along with three HD-XA2s.

I prefer HD DVD and use Blu Ray for only Blu Ray exclusive titles. No matter which you buy you are getting a very good upscaling player for SD DVD.

I agree with posters here who say find the most HDM content that appeals to you and get that if you can only afford one format. Get SD DVD for the other format. If you can afford two formats, you will certainly be twice as satisfied.

Not to add any fuel to some of the fires here, I can say that HD DVD always has great PQ, some of my Blu Ray discs have a lot less of that WOW factor. Some look pretty washed out.

I have an excellent 1080P display which makes any flaw visible.

The HD sound from HDM is as big an improvement as the PQ, so do not ignore that part of your theater.

If you can find an XA2 snap it up. It is the top of the HD DVD heap. And the best upscaling SD DVD player around.