A good BUDGET 5.1 or 7.1 sound system for a PC?

-I originally was going to buy the Corsair SP2500's but they're 2.1 and I REALLY want a 360 sound experience when playing a game like Battlefield 3 or Skyrim. Now.. i know that a sound system like Logitech Z5500 is awesome BUT i really don't think I'll need that because I'm moving my PC from the living room to my bedroom which is like 3mitres by 3mitres area. So how powerful should the sound system need to be?? I will only listen to it in the room and not in the shower downstairs.



-Also.. I listen to Dubstep and DnB a lot so it would be nice to have a good clear sound. I'm currently just using a headset all time which is Turtle beach X11's and i like them, I'll just use them at night once i get the sound system.



So.. in summary.. I want to hear bullets and explosions behind me as well as dragons shouting from the proper angle as they fly over me( skyrim lol) and a good music experience for Dubstep and DnB ALL IN A 3mx3m room. will a 70W 5.1 system do it for me?



how about one of these 3:

-http://www.ncix.com/products/?sku=55970&vpn=980-000430&manufacture=Logitech

-http://www.ncix.com/products/?sku=25952&vpn=M1550&manufacture=EDIFIER

-http://www.ncix.com/products/?sku=51724&vpn=51MF4105AA002&manufacture=Creative%20Labs



are these good?



Thanks in advance!