the only thing in the specifications you are going to get that is going to be of any use is the bass.
if you really want some bass.. you have to look for a frequency response that gets down into the single digits.
something like 4hz or 8hz would let you know the headphones will be producing some bass in the 20hz - 30hz area.
anything else is a complete guess.
you could check the power requirements and the ohm rating.
anything above 40 ohms might be too high and require an amplifier.
i know the 60 ohm headphones are supposed to require an amplifier.
but
some headphones are 70 ohms .. and they really really need an amplifier (like hardly no sound at all)
the ohms is best to know if you can run them off a soundcard or if you need a dedicated amplifier.
the power rating is said in mW
higher numbers mean they will either not distort.. or you dont have to worry about them suddenly dieing from listening to them loudly.
i have found it to be true that the higher numbers means they wont distort.. but could die if they are somehow abused.
my experience was brief.
there wasnt any distortion.. but perhaps i forced the speaker cone to move in and out more than it was designed for and it broke (or the speaker itself was defective from the start).
bursts of power are not really important compared to the constant or RMS or 'nominal' power.
if you go over with this number.. the speakers will do one of three things:
1. distort
2. suddenly die one day
3. both
some people consider 'suddenly die' to be different.
it could be a scratchy noise that comes one day.. and the scratchy noise would probably get worse and worse until the audio output stops.. you bump it and it might come back on and then completely refuse to play any audio no matter how much you bump on it.
or
suddenly die might mean the speaker is playing and the thing fizzles and stops playing audio completely.
usually the scratchy happens and it lasts until the speaker slowly dies and never returns to life.
depends on how the speaker is made, as to which way it dies.
but
it could also depend on how the speaker was abused, as to which way it dies.
**edit**
if you are in the market for headphone surround sound..
i would probably suggest trying this combo:
http://www.bestbuy.com/site/Turtle+Beach+-+Ear+Force+DSS+7.1-Channel+Dolby+Surround+Sound+Processor+for+Xbox%2C+PS3+and+PC/1145414.p?id=1218224794909&skuId=1145414&st=headphone surround&cp=11&lp=14
and this:
http://www.bestbuy.com/site/Sony+-+Extra+Bass+Over-the-Ear+Headphones/9227561.p?id=1218062719186&skuId=9227561&st=headphone surround&cp=12&lp=1
i havent heard the accuracy of the surround sound box.. but apparently it is the same thing that comes with most of their surround sound headsets that get good reviews.
i have heard the headphones before, they sound good for anything from rap to classic rock.
when you move away from rap and pop.. you might have to bump the bass down if you are overly picky.
but
for movies and video games.. the bass is welcomed with wide open arms (as well as the base).