Bose Companion 20's if you're looking for a 2.0 setup, but for the best go for Bose Companion 5's. The USB connection gets rid of any hiss or other nonsense that would be heard through the 3.5mm output! The bass module on the Companion 5's puts out quit a punch, and depending upon your room, will sound epic! The "simulated 5.1" sound is great too when gaming. The vocals are so clear. I absolutely love those speakers. Every time I am playing a game or listening to music, I hear things I haven't heard before. It's amazing!
Either way, you can't go wrong with any of Bose's computer speaker offerings. They all sound great.
This is coming from a guy who use to sell home audio for 6 years. I absolutely could not stand Bose at all. Then one day I gave the Companion 5's a thorough testing at work and was blown away by their quality.
I now look to Bose for any audio product. Granted if I can afford it, they're pricey!