DONT DO IT.
I asked the same question here a few days ago:
http://forums.overclockers.co.uk/showthread.php?t=17792005
Some very helpfull posts led me to
http://www.head-fi.org/
A very helpfull community to be honest but they sure know their stuff about Headphones.
With that budget, a 5.1 headphone set would be a complete waste to be honest in terms of audio quality, especially if you want to watch films.
A solid pair of stereo headphones with good seperation will out perform ANY 5.1 headset within your price range.
As you can see from the thread I started, I was in exactly the same position as you.. I also work nights and mainly get to use the computer late evening/early morning.... in the end, common sense prevailed and:
http://forums.overclockers.co.uk/showpost.php?p=10325986&postcount=8
I have a pair of Audio-Technica ATH-A900 Art Headphones on their way for a tuppence over £100 DELIVERED. Most UK stores offering them for £155, yes they are imported but that does not bother me, it is a very reputable site.
These will BLOW ANY 5.1 headset out the water and they will last 4 times as long most likely and Can also be used for Hi-Fi and TV as well as gaming.
I also got carried away and also have a Creative X-Fi Fatal1ty Premium on the way as well but with those 2.. my head will definitely be rocking
Just my 2 pence worth. Email in trust if you need specific details
