Looks like he has decent portables covered with the JVC's, and a great full size in the AT's.
Metal is his genre, AKG works here but as mentioned you have great options.
Grado (Made for Metal/Rock) I think 80's are a great entry point, even the 60's are great to start.
Very love it or hate it headphone, I'm in the Love it but can't wear the damn things due to the comfort. I go on long jam outs but after an hour my ears are swiss cheese.
Beyerdynamic DT770/80ohm is another great Metal can. Outstanding build quality, top of the heap for comfort. Deep hard hitting Bass (When it's needed), great detailed mids and a nice smooth treble, BIG soundstage for a close can...My Go-To set.
Koss DJ100/TBSE Thats right, another pick for metal. Bass can be light for some, But what is there is tight and greatly layered. Mids are outstanding. Best I've heard in a cheap set.
Highs are rolled off (Think Senn). Can be very amp picky, Amps not needed but amped proper they really shine. Punching WAY above their low price. Neutral to slight above amp needed.
Gotta add M50 pads, it's a must. Total different sounding set just with a pad swap.
CAL-what needs to be said? works with all music,
M50-I hate these cans, BUT they do work really well with Metal/Rock. The V-shape sig helps, a fun set for sure. Don't pay full retail at $150, soundpros sell them for $99 off and on (Right now $99)
At full retail they are outclassed by the Beyers mentioned above...
This is a good start, for cheaper sets, others can chime in on higher sets. I stopped at the Beyers and feel no need to go up the chain right now.