[iSennheiser]

  I'm not expert of classical music but you might want to give a look for Bowers & Wilkins P5 too. If you live near Apple Store you most likely find pair to listen there. http://www.amazon.com/Bowers-Wilkins-Mobile-Stereo-Headphones/dp/B003IHUHGE/ref=sr_1_1?ie=UTF8&qid=1379263528&sr=8-1&keywords=B%26W+p5
 
Comfortable, durable, great sound, and very portable.
 
Ordering replacement cables from B&W have been frustrating for me though. It shouldn't break in normal use but my dog seems to like destroying those cables...

P5 is a definite No to Classical Music, its hard to find headphone that is good for Classical Music, simply you  need a flat signature headphone to enjoy Classical Music, because simply Concert Hall has their own acoustic engineer that change the sound signature depending on the music being played( example, Chamber, chinese music, Piano concerto or Violin concerto, or some stravinsky where impactful timpani is dominant). So , I only could recommend flatter headphone or warmer sound, definite no to V-shaped sound, or Bass emphasised. You need clear sounding like HD600/800 or stax 009

 

[zorin]

I am looking for a headphone that is good for classical music especially with a lot of violin and high instruments. My budget is $300. Max $350

If you want to listen to music outside of your home then you need closed headphones. You might consider Beyerdynamic DT660. These headphones are often overlooked. Check these threads to know more about them
- http://www.head-fi.org/t/126171/beyerdynamic-dt-660-880-990-pro-a-comparison
- http://www.head-fi.org/t/559542/i-truly-believe-these-are-one-of-the-best-classical-music-headphones-ive-ever-heard

 

[iSennheiser]

Fostex maddog will be your choice . hehe its that good

 

[AphexAcid]

For that price range, Ive found the akg 701 or 702 soundstage is unbeatable for classical

 

[Mambosenior]

Like Zorin, I recommend the Beyer DT660 at your price range. The DT880 is also very fine but I still prefer the 660.

 

[Claritas]

For classical with an emphasis on strings, I agree with everyone about Beyerdynamics. I'm surprised that no one mentioned Grados, which are amazing at smaller-scale string works.

 

[iSennheiser]

For that price range, Ive found the akg 701 or 702 soundstage is unbeatable for classical

Yes AKG 701 and 702 is one of good one for classical music especially Jazz. AkG is generally good for classical. recommended,