THANK YOU for throwing me a thread EXACTLY in line with my tastes. I've been a crazed listener for almost a decade now. I've been to so, SO many corners of the scene. Here's some recommendations:
Coroner (Progressive Thrash Metal)
Mindblowing band in every sense possible. Heart-pounding polyrhythmic riffs, extremely technical and sophisticated leads, and relevant, human songwriting to top it all off.
Only downside are the vocals.
Ex: http://www.youtube.com/watch?v=V2uhQPpQAYs
Animals as Leaders (Progressive Metal)
Innovative guitarwork, heavily atmospheric, capable instrumentalists.
Only downside are the LACK of vocals ^_^
http://www.youtube.com/watch?v=5lrwYPhHThc
Megadeth (Technical Thrash Metal)
Solid thrash band with some of the most ear-catching riffs in the genre. Politically charged songwriting to accompany it.
Downside: Have lately gotten stale, extremely corny lyrics (used to be far more substantial)
http://www.youtube.com/watch?v=UrevUFE_yGA
Kalmah (Melodic Death Metal)
Amazingly atmospheric, great hooks and themes. Incredible use of synth. Manages to supercede the cliches of generic melodeth, goes beyond vikings and into politics, religion, and deeper social matters.
Downside: Songs can feel somewhat rushed.
http://www.youtube.com/watch?v=IgJyahHXdo8
Artillery (Technical Thrash Metal)
The catchiest, poppiest band in the mix, however, some of the most blistering riffs in this collection. Very sophisticated songwriting.
Downside: Lack of layering
http://www.youtube.com/watch?v=Ebgca0odXxQ
Opeth (Progressive Death Metal)
Makes Satan break into tears. Beautiful, atmospheric, incomprehensibly proggy, mindblowing songwriting, envelops you in a vortex of emotion and never lets go. Steller band. Mikael Akerfealdt is a genius. At that, all of the prior musicians are
Downside: Acquired Taste
http://www.youtube.com/watch?v=jecDFEfigoI
Sorry if that was something of a lengthy post, I just had to.
Enjoy listening.