Still unsure of what direction I should go. I currently have HD 555's, but I'm using onboard sound. Should I be investing in a high end sound card to get the most out of these headphones, or a mid level card?
I'd like to spend at the most $150-200.
But I don't want to buy something high end and not get use out of them because my headphones are not good enough.
If you can spend up to $200, I say spring for a new set of headphones, like the HD598s. Check the deals thread for sub-$200 prices on those.