I'm not so sure about the ATH series. I heard they are good for vocal work, female voice, etc...But they seem to be a little too colored for classical music playback. Anyone agrees?
I'm currently using AKG K271 MKII, but, I keep thinking the high frequency of this headphone is a little too bright, making it not that balanced for classical. The strings sounds too good (compared with other instruments), which makes the hearing experience a little fatigue. Although I agree there will be no better closed back 'phone under $300 that can play classical better, or is there (say, the D2000? )
In the past when I choose headphone for classical, I usually go for a German made 'phone, rather than a Japan made. Denon seems to be an exception. It's quite balanced and natural. I heard the classical under D2000 before, and am impressed. But D2000 is better for pop, vocal, and other type of music, so I can't help wondering if its more expensive brothers, D5000 and D7000, will give much better performance in classical. (and I'm glad to hear comments from shane55 to confirm this, thank you! ).
It seems that there are only a few flagship that is closed-back, so we are left with not much choices. How about the STAX 4070? That's the only closed-back electrostat 'phone available in the market ... can anyone comment on its performance in classical? 
Edited by Pabro - 5/24/11 at 2:21pm