I love a full range of metal from the classics to the extremes. I enjoy stuff from most of metal's sub-genres (doom, death, black, viking, folk, thrash, classic, prog, power..) - the only metal-related subgenres I'm not much into are metalcore and nu-metal.
Some favorites:
Black Sabbath
Fates Warning
Blind Guardian
Summoning
Windir
Enslaved
Burzum
Sleep
High on Fire
Kyuss
Morbid Angel
Bolt Thrower
Agalloch
My Dying Bride
Wyrd
Bal-Sagoth
Bathory
Dissection
Godflesh
Motorhead
Iron Maiden
Judas Priest
Ulver
Symphony X
Slayer
Xasthur
In The Woods
Falkenbach
Death
Cynic
Demons & Wizards
Windham Hell
The Meads of Asphodel
Shape of Despair
Celtic Frost