BigIg 90% percent arent good since they are stereo and others are stereo with sub drivers and just simulate (rather badly) 5.1 (think those crappy usb sound cards which only have a stereo audio plug but has the ability simulate 5.1, most of them use the same crappy chinese and cheap technology)....
there are a couple of good ones but dont produce anywhere as good sound as you get with the logitech x-530 5.1 speakers which can be bought for au$70, you may say they are more discrete since it is headphone therefore its worthg paying a minimum double the price, ill say yes if they were discrfete but all true 5.1 headphones dont have all the speakers internally, actually some are external like the center speaker or the subs therefore eliminates the discrete sound...
all is not lost there is one where the speakers are in the headband, the top of your head and its tubed to your ears, its the only true discrete 5.1 but initial designs suggest that all the auido from the speakers get mixed together while its sent to you ear meaning it eliminates true positional sound, also i meant initial designs is meaning its bieng prototyed and isnt available for retail but i wont consider it even if it was on retail and offered slightly superior sounds to the logitech x-530 because it will cost more than us$500.
if you still intend to get one, dont cheap out on one, avoid usb ones as its most likely the chinese usb sound card integrated into the headphone, otherwise its a slightly improved one, so try to get ones with connecters for front, rear and sub/center. also check for reviews and user comments. lastly for the love of god please avoid the wireless ones...
if you must ask which one i might consider, it will be zalmain 5.1 ones, its old but that means it can be picked up quite cheaply, but it offers true 5.1... if really wanted to get it ill get it with the intergrated mike version which is useful for online gaming