Seriously, headphones are almost always two speaker systems. You know, a left and a right. With only two speakers DTS, Dolby or any of the multichannel systems are pretty much irrelevant. This is because in order to use virtually all headphones the sound has to be mixed down to two channels.
I understand there are some headphones designed for surround listening. AFAIK they are all designed for computer gamers. That IMO tends to discount any audio qualities they may or may not have.
Here's a thought! Buy the best sounding headphones you can afford. Plug them in and listen.
Buying two channel headphones based on their ability to play surround formats is ludicrous.