M50 will be horrible for gaming, its soundstage is pretty weak and flat IMO. CAL! is probably a better bet.
+1. M50 are a bad idea here IMO.
I'd also add the Bose AE2 (alongside the CAL!); yes they cost more, but they're among the most comfortable headphones ever made, and isolate better than most of their competition (including the M50) at the same time. Nice, smooth, all-rounder sound signature with pleasantly rolled-off highs that make them very non-fatiguing and un-offensive for long listening. They also have enough bass impact to make games and movies satisfying, and a good soundstage to boot. Just don't expect electrostatic speed or accuracy and you'll be fine.
CAL! are about half the price any given day though, so I wouldn't discount them (this by itself is a "feature" imo - haha). It's been a while but I want to say the sound-stage on the AE2 will be better, while the CAL will be better in the treble region. Neither are bad though.
Have heard the HM5 has a good soundstage and decent bass response, Look into those.
Please don't suggest things you haven't personally heard. It doesn't help.
