I actually have the M50 and it was also my first phone that I got for christmas. I listen to a lot of metal, trance type stuff also. As your first phones, I promise you will love them. If you really want to come into the audiohphilia world, you'll eventually realised that the mids are slightly recessed and it will make you want more. All in all making you buy perhaps, an amp, better source, or better headphones.
I'm really sorry for opening an old thread, but about 2 weeks ago I ordered some M50's and well, long story short, USPS lost them... I think I might buy them again with another seller from Amazon. Anyways, I listen to everything like Rock/Metal, Hip-Hop, Country etc... I really want to hear the guitar solos and vocals etc... and you said that the 'mids are slightly recessed', so will those things still sound good?
My brother gave me his Solo HD's a couple of years back and I've been using those, will the Mids and highs in the M50's sound better than the ones in the Solo HD's? (I know dumb question.)