I don't really understand the categorisations: what's the difference between death and black metal? Is it just that lyrically black metal is really sick and trys to offend people? Does the vocal style have anything to do with it? I generally don't like growling, I prefer people who can sing.

As for bands; well, meshuggah are technically excellent with a brilliant guitar player. Not really into them but might end up that way.
I heard some Opeth for the first time last night and was very impressed with their sense of melody, variety of dynamics, tightness of execution and variety of scale use. I would love to hear more.
I have heard a little Morbid Angel. They have an excellent guitar sound with a top soloist.

What would you guys recommend for musicality and technical competence by these or other similar bands?