i hate the word "progressive" and people should avoid using it when describing opeth, even when the word applies, because the unitiated will assume you are speaking of a band that does songs about chess and history and robots or something. you wont get any new opeth fans this way.
i especially am annoyed by people describing damnations as prog, since this album is very simple in a lot of ways and also seems to have a lot of classic-rock/rock and psychidelic influences, but isnt proggy to me. somthing can be very good, while being neither "progressive" nor "technical" -- another overused gaywad word. i think deliverance gets pretty proggy, in a good way. opeth is like if you took the gay out of prog.
prog is a term used too often to describe bands that play well and have intelligent lyrics. like porcupine tree or kings x. save prog for really really edgy shit that is unlistenable to any but the most obscure jazz freaks.