progressive metal

^ I agree though, APSOG deserves a mention. it's one of the best 5 prog metal albums imo.

I strongly recommend (again!) Psychotic Waltz - A Social Grace. It's hard to get into and the vocals may not be for everyone, but for me it simply is the best prog metal album ever. It's full of creative genius.
 
Would Blotted Science count as progressive metal or technical metal? They're good too. The lines get blurry when it comes to technical/ progressive/ avant-garde/ experimental.
Also I listed Anekdoten (not really metal), and Oceansize without thinking, but they are progressive.
 
I'll be the old fogey and mention Savatage (Gutter Ballet & Streets), and second Queensryche (Rage for Order & Mindcrime).

Back in the day those were always the first two responses you'd get to "progressive metal?".