These are the two best under rated, bang for the buck audio gear for your laptop or desktop. Are they the absolute best, of course not. But if you want to jazz up your otherwise drab computer sound, these guys will do the trick and they are cheap enough to have one for all of your computer equipment..
I have these guys installed on my laptop and desktops and they improve the sound tremendously. When paired with a good set of amplified speakers, like the Audioengine A5's, its a hard combination to beat for a shoestring budget.
Audioquest just came out with an improved Dragonfly and it is the bomb for use with headphones. I bought one for my dad to use with his laptop and Grado's. Man what a difference.
I know you can spend more money on better stuff, but for the price and bang for the buck, this Audioquest stuff is hard to beat.