I was considering getting a pair of M-100s, but it looks like they aren't quite as audiophile friendly as I'd hoped. I'm looking for a fairly transparent set of headphones that will work with a wide variety of genres and are suitable for mixing, and from what I've been reading the M-100s don't fit that bill, so I'd love some recommendations for other headphones to look at. I primarily listen to modern metal and electronic, but no genre is outside my interest, and as I'd like to be able to use these for mixing a realistic representation of the music is what I'm after. Isolation doesn't really matter to me within reason (I don't want everyone else in the room to be able to hear my music as well as I can, and at low volumes I'd like the headphones to be relatively silent as far as sound leakage is concerned), so I don't have a preference as far as open vs. closed goes, and I'd like a fairly open soundstage. I'm also more than willing to get an amp if necessary, so I don't have a preference as far as impedance goes so long as I can drive the headphones with a semi-portable amp. Headphones I'm considering at the moment include AKG K550s, PSB M4U1s, and the Philips Fidelio L1, but I'm open to suggestions so long as they fit the above criteria. My total budget is around $300, but a little over is fine. Whatcha think?