I don't know if you tried these guys already:
Agalloch - elements of opeth (accostic guitars mix of clean and agressive vocals good songwriting and epic sounding)
Bloodbath - Good death metal ESPECIALLY the song breeding death (my fave death metal song ever) Although you may have already tried them being an opeth fan.
Old mans child - very dimmu-ish in sound in parts but i think there songs are more solid and memorable.
Alchemist - they are an aussie band i like them you might too. Try the songs chinese whispers, yoni kunda, austral spectrum.
Matyr - Particularly the song warp zone, kick arse riff on the start of that song.
Thryfing - good sounds with these guys, nice melody while still sounding hard.
Vintersorg - good musicianship on this, good song writing.
Also if you like brutal death metal try out psycroptic they are from tasmania, some good stuff to be had there.
Alot of this stuff you can find at
www.mp3.com