i just bought the Logitech Z-3, http://www.newegg.com/Product/Product.asp?Item=N82E16836121114 , for 49.99 at Fry's. for some reason, the Z-3e was 60 at Fry's and the Z-3 was 50. yet at newegg, the Z-3 costs more 
i have the (old ) Logitech Z-640s, they have updated them to this: http://www.newegg.com/Product/Product.asp?Item=N82E16836121118 . If you're looking for cheap and awesome sounding 5.1, that is what you want. it's analog only, but if it's hooked to your PC, it's no big deal. the speakers sound amazing, i get comments all the time with people telling me how badass they are.
i have the (old ) Logitech Z-640s, they have updated them to this: http://www.newegg.com/Product/Product.asp?Item=N82E16836121118 . If you're looking for cheap and awesome sounding 5.1, that is what you want. it's analog only, but if it's hooked to your PC, it's no big deal. the speakers sound amazing, i get comments all the time with people telling me how badass they are.