See the topic ^^
Feel free to offer your own suggestion too !
After going the rounds of virtually all mid-priced (HD650, K702, D2000 etc) and a couple of higher priced (LCD-2, HE-500) phones, I finally setted on the Beyer DT880 Pro for orchestral/classical. It's beautifully balanced, extremely neutral, very comfortable and bargain priced (currently $195 on Amazon). Only possible snag is a fairly innocuous peak around 6.5 khz, which may or may not bother you (dissipates as the phone burns in). If it does, you either need EQ, if you're listening from a computer, or, as I do, use them out of an integrated amp with tone controls (-2db). The 880 generally competes with phones in the $500 area, and in terms of classical can compete with phones even twice that price. (One exuberant reviewer even prefered them to the HD800).
What are you waiting for?