thanks for the information Verno & Bucky, and my apologies to Sepharo
the reviews for the Sennheiser HD595 seem very good, but it seems discontinued in favour of the HD598 which is even slightly better. the ATH-AD700 seems great too; but the impression I got from reviews was that the hd59x had better bass. i think i might go for the hd598.
the Antlion Modmic is important too; I am using a yum cha desk microphone and it does get quite in the way and has below average quality.
however, i am not sure about the sound card and whether it'd be worth it. i can definitely hear a vast difference between my onboard chipset & my creative live 5.1!, but wondering if getting a pricier card would make too much of a difference. i have a dual boot too; so linux compatibility is an extra complication.