open if its gonna be home only... but if you got for LAN and stuff, may i suggest a closed set? my ATH A900's work very well for gaming, let my friends try it during gaming and i never get it back till we go home lol.
oh. just saw your budget... haha i do believe u might get a better deal if you go and ask for a pair with good soundstaging and imaging. Soundstage makes your hearing environment sound "wider" and thus you have a larger range for positioning the sound source, and imaging to fine tune the precise location of the source..
frankly it boils down to how used u are to a particular set of cans. i can play l4d with portapros perfectly well.