The THX headphone amp is getting a lot of good reviews:
I use the Schitt HEL 2.0 for my laptop/desktop w/ a pair of Sennheiser HD650s and it's a good little setup for my use. When I'm working from home or gaming on the laptop I strictly use headphones and the Schitt was worth the $200. I like the tactile quality of the volume knob, the DAC is really quite good and it's relatively portable. Separate power and sound inputs as well.