The Lepai is a decent sounding amp, I have one, but by the time you buy it and a more powerful power supply, for not that much more, you can buy a SMSL SA-36A, which is what I'm currently using to power the Pioneers, and it is considerably better looking and better built, with actual binding posts, and no tone controls, and it comes with a proper power supply, it's about $49 shipped. They use the same chip, and do pretty much sound the same though.
I found the analog audio out on many computers to not sound all that great. I'd consider at some point, a USB DAC assuming your sound card doesn't have a digital output. Mine does, so it runs to a Harman Kardon AVR 330 that functions as my DAC and sub controller. From the h/k's preamp outs, it goes to a Little Bear P1 preamp, and then to the SMSL SA-36A.
These small T-amps do sound better and more powerful with a preamp in front of them, though they can be used stand alone of course.
This is my computer setup: