Hi there, troopa!
What did you ultimately decide on getting? I'm in the same boat you're in and I was thinking whether to get the K550 / K545, the HD 598, or something else altogether. I also listen to a lot of female pop and ballad vocals so it's important to me to find something (easy to drive over-ears) that renders female vocals well with a good amount of clarity, soundstage, and something sort of euphoric sounding. Sorry to be riding on your post, but can anyone help me make a decision as well? I don't really have experience with cans, only IEMs. And to give an idea, I have a pair of Westone 2's and Fitear F111's. :)