hmm ....
Some of my favorites .... (anything with Makael Akerfeldt is guaranteed to be f***ing awesome)
Opeth .... Best Melodic Death
Bloodbath ... Best Death-Grind
Edge of Sanity ... Excellent Death metal
Katatonia ... Excellent Doom/Death Metal
Also ...
Novembers Doom ... American Doom Metal
Saturnus ... European Doom Metal
My Dying Bride ... Classic Founding Fathers of doom metal
Death ... The band that basicly started Death Metal ... RIP Chuck
Older Anthrax, great thrash ... stuff like Metal Thrashing Mad is just friggin awesome
Overkill ... Great Thrash Band
Kreator ... Great Heavy Thrash Band
At The Gates ... The founding fathers of the whole "Gothenburg" Melodic Death Metal Sound (listen to Burning Darkness if you get a chance, that track is insane)
Macabre ... Its teh Funniest Death Metal band around. Their tracks are all about different Serial Killers.
Iced Earth ... Great American Power Metal
Timecode ... Great Death Metal band from Chile (samples are free on their webpage
http://www.timecode.cl)
Cephalectomy ... Great Canadian Death Metal Band
Cannibal Corpse ... Excellent Death Metal, slightly offensive lyrics
Carcass ... Awesome Old School Death Metal
as mentioned above ... Pink Cream 69 ... Great Melodic Metal band ... not very heavy though
Dragonforce (Which Used to be known as Dragon Heart is quite good. You gotta like power metal to like it though. It's an improvement over most other power metal bands IMO)
Nightwish ... Great Power metal, Tarja's voice is awesome. That pretty much sums it up
Haggard .... full orchestra plays death metal mixed with folk mixed with classical. They have a DVD out, its actually pretty cool to watch.
Though technically not metal ... Kyuss ... Probably the greatest Stoner Rock band of all time
Cradle of Filth and Dimmu Borgir are not Death metal at all. They are a mix of goth and a poor attempt at black metal. (dimmu is not so bad, but i really dislike the vocal style used by COF. also, IMO, every COF song sounds the same.)
If you want good black metal, listen to some Einherjer, Immortal, Enslaved, Satyricon, Nazgul, Windir, Emperor, Summoning, Marduk, old Mayhem, Bathory, Finntroll, Ancient, Arcturus or about 1000000 other black metal bands.
If you want I may be able to help you out with locating some samples, and with more recommendations. feel free to shoot me a PM.
*note* I very much hate rap and "nu-metal" (which I do not consider metal) I also don't care too much for most punk or hardcore.
If you want "real" metal (death/black/grind/doom/thrash/classic heavy/power/progressive) I can help you out ...