When buying headphone + amp, don't forget the electrostatic alternative. For primarily classical, the Stax SRS-2020 system is hard to beat for the price, and if you want to spend/waste more, the 3030 is probably the best price/performance ratio hi-fi set that you can get (debatable). The 2020 will drop you $449 from Audiocubes, the 3030 $779. I'd say go with the 2020, get decent IC's - HeadRoom sells DiMarzio IC's which are pretty good for $89, although you can probably ebay them for cheaper - and that still leaves you with $462 to get your source. For that money, you can do pretty well, but I'm not the best person to advise you here. The 2020 is supremely comfortable, too, although it can get a bit hot after a few hours.
Alternatively, if comfort isn't an issue at all, the Stax SR-005 canalphone system sounds as good, and in some ways better, than the 2020, but for a bit less cash. It's not quite as extended in the top end, and the soundstage is narrower, since it is a canalphone, but the bass is deeper and the mids are a bit more lush and resolved. I have the SR-001 Mk II and I love it, preferring it to many more expensive setups - but they're uncomfortable for long periods of time. My ears got used to it - but that shouldn't be a part of a good headphone experience.
Think about it. Electrostatics aren't really that expensive - the amp is simply included in the price. When you compare them against similar dynamic setups, they actually offer better bang for the buck. I'd say Stax 2020 all the way, and 3030 if you can stretch your budget.