About Buying 5.1 speaker for pc

I want to buy a 5.1 speaker for pc. I have choosed some speakers given below.
1.Creative Inspire T6300.
2.Logitech Z506.
3.F&D F6000.
4.F&D F6000U.
Now please tell me which one is the best for computer.Which speaker should I buy???Please reply as soon as possible I am totally confused.