[Datsun]

Hi everyone. I recently got a Fiio X3 for my birthday, and I'd like to get a pair of headphones to compliment it. My budget is loosely set at around $300, but I can stretch that by a reasonable amount if needed.
 
Some notes that may help:
 
-I listen to a little bit of everything, but focus mostly on classical, jazz, rock, county, and blues.
 
-Open vs closed: I'm open to all suggestions. I will occasionally be using these headphones in semi-public places (think quiet lunch  room or a library), but unless the headphones in question have insane sound leakage, I'm not too worried about it.
 
-I own a pair of cheap HARX-700 headphones and a Sennheiser PC-350. I've also given a friend's JVC HA-S500 and Sennheiser HD202 a good listen.

1. Between the two headphones that I own, I'd say I like the PC-350s better, but they lack a bit in terms of bass and the highs are a little too exaggerated. 
2. In comparison to the other headphones that I've given a listen to, I'd say it would be a toss-up between the JVC HA-S500s and the PC-350s. While the bass of the HA-S500s were too exaggerated for my liking, the PC-350s were lacking in that area. The HA-S500s also sounded a little muddy and lacked definition, and I found it a bit difficult to listen to for extended periods of time.

 
-On-ear vs. over the ear, I don't really care. I've noticed that I'm pretty tolerant to uncomfortable headphone designs.
 
-I don't have an external headphone amp.
 
- I am NOT adverse to the idea of used headphones or equipment.
 
-I will not be exercising, working, sweating, bleeding, etc when using these headphones.
 
-Budget is in USD.
 
I'm very new when it comes to the world of audio, so I apologize if I'm not conveying my thoughts very well. If I've left out any information or if  you just have a question, please feel free to ask.
 
Thanks for your time,
John