[ArmAndHammer]

I LOVE LOVE LOVE my Grado RS1. For the music I listen to most I can't imagine a better headphone (though I'm sure there is). I am powering them with a Little Dot 1+. I'd love to try something new. Something similar but different enough to be worth trying. 
 
Music is stuff like Dave Matthews, Jack Johnson, Mumford & Sons, acoustic versions of rock and metal songs...stuff that NEEDS great mids and nice highs with accurate but not crazy bass. 
 
First thought I had was maybe the HE-400. Or MrSpeakers Mad Dog?
 
Thoughts? Trying to stay around $300 new or used.

 

[sinnottj]

Hardly a leftfield suggestion, but what about the Sennheiser HD600? Awesome mids, full but not overblown bass, detailed but smooth highs. Incredibly natural tone, one of the most musical headphones around, in my opinion. Very comfortable as well!

 

[ArmAndHammer]

Some reason I always looked past those and the HD650. The HD650 probably due to cost though I did splurge a bit on the RS1 but I'm a Grado fanboy so that one made sense not to mention I only paid $200 out of pocket for them. I'll definitely give them a closer look. 

 

[KG Jag]

Shure SRH 940.