I've really been getting into some more progressive sounding metal these days. I've been listening to Opeth non-stop for awhile now. I'm truly amazed by that band, and I'm looking for similar metal bands that defy genre limitations but I don't know where to start. Any recomendations on bands that use complex compositional structures, odd time, epic sounding songs, etc...but remain metal in essence. Some bands that I've come across in my research, but I have not checked out yet are: Dream Theater, Pain of Salvation, Ayreon, and Riverside. Does anyone have any recommendations of albums to check out by these bands or other bands that are essential listening? Thanks in advance guys!!!