If you want a fantastic set of 5.1 THX Cert. speakers right out of the box, and have the funding to buy them then I would look into the Logitech Z-5500 Set. Comes with a wireless remote, 5.1 surround sound, bass control, treble control, 10" 500w RMS subwoofer. Its truly a great system and I can say this as it is what I have owned now for 2 years after both having "built" surround sound systems for my PC (Quality parts like Onkyo Receivers, and pre-built Bose systems), and cheaper end pc speaker sets.
*Note: I use these every day for my blu ray movies, games like Call of Duty MW2, Dirt 3, Left 4 Dead 2, X3: Terran Conflict, and even RPG Games like Oblivion & Divinity 2. I can tell you now that not only will they not disappoint, but will also end up exceeding your expectations due to the fact that it is near unheard of to have such performance from any other preboxed system on the market.