We don't know your room specs, or other equipment/personal focus regarding the type of media or content you intend on enjoying. I could also say upgrade to XXX, but it may miss the mark dramatically, especially when a budget comes into play (hint, hint).
I currently have a computer equipped with a Logitech Z-5300 5.1 surround sound system http://www.amazon.com/Logitech-Z-5300-5-1-Channel-Surround-Speaker/dp/B0000C20R9 What should I upgrade it to?

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