In terms of FR, the HD560s are quite good, but I feel like they compress the dynamics a bit. Probably wouldn't be the only pair I use (but I'd always check on multiple anyway), but they are hard to beat in terms of price vs performance. The Beyers can be good for treble analysis in particular, but I have a big head and they are just not comfortable for me. Still, those would be my two picks.

Bummer, PC38x is one of my favorite headphones period. Except for a driver going bad and having to buy a whole new pair because Drop doesn't sell parts... People can hate on "gaming" things all they want, but sometimes it's just more convenient to have the mic attached and if the headphone also sounds great, why fight it?