Lf amp or amp/dac for dt770's and a few digital inputs!!!

Lf a amp or dac/amp for my beyer dt770's. I plan on using it with my pc and 360. I have an asus xonar hdav 1.3 which if I'm not mistaken has decent dacs already. I just want to be able to take full advantage of my headphones. I don't want to pay more than $250ish if I don't have to. Or should I just get a astro mixamp? Idk how it favours to 250ohm headphones though.Thanks
Edited by spitfire91104 - 10/27/10 at 12:38pm