I can't give a list of purely Metal bands. But in terms of the rock genre, here's my list.

1- Dream Theater
2- Pink Floyd
3- Metallica (before James quit drinkin' and became a pussy)
4- Iron Maiden
5- Guns N Roses (1992 and back, not the new crap)
6- Anathema
7- Marty Friedman

and misc. others.