Let the hive mind of Engadget get that for you.
"I'm looking for a pair of quality headphones that aren't seemingly made of glass. I'm an avid BMXer which causes me to frequently bash on any type of technology that joins me for my daily riding. I've been through the higher quality headsets in the Skullcandy line as these are supposed to be built for "abuse," which is laughable. I cant wear earbuds or canal buds, as my large ears seem to have a repelling property upon anything that sits in them. Wired or Bluetooth doesn't really matter, but I need something that can hold up to taking a few hits every now and again. I'm trying to keep 'em under $150. Thanks!"
You are correct. HD DVD add-on does have inferior sound compared to PS3, HD DVD standalones and Blu-Ray standalones. It is still not crap, but you do get DD 5.1 instead of TrueHD or DD+ thus some difference.
For majority of people though, this won't come as a huge problem as they are quite obviously very happy with DD 5.1 on DVDs to begin with and HD DVD add-on price right now is low so it's kind of smaller sacrifice.