If you can afford one with a headphone amp that's good, though you said you were using a receiver? Does that have a decent dedicated headphone amp? If so, it might be just as good, though I have no idea which way to go here, AV Forums might be the place to check out for more info on this.
I dont use my A/V amplifier for the PC, but i thought it could be an "option" to this headphone AMP
I dont know if its dedicated headphone amp or not (i doubt it)
Its a Yamaha RX-V640