All y'all called it.
1. Thrice - Depending on the day, Thrice could easily challenge Opeth or PT for a place in my top 2. As it stands, they're my favorite besides those two, with a catalog that is consistently great and charts an incredible musical progression from their hardcore roots to the art rock style they have now. All of their albums are amazing, with my favorites being Artist in the Ambulance and The Alchemy Index. Listening to The Alchemy Index all the way through is probably one of the greatest listening experiences someone can ever have, but what makes the set even better is that you can listen to any of the volumes individually and they still retain their power, each one giving an excellent microcosm of various aspects of the band's sound, from hardcore to folk rock.
I've previously mentioned songwriting as something that is very important to me, and to me Thrice is almost unmatched in this category. They've honed their songwriting craft to a razor edge - every song is chock full not only of great segments but they interweave in a way where you could never imagine them in another context. Songs like Blood Clots and Blackholes, The Messenger, or The Abolition of Man are all under three minutes, but are some of the most intense pieces of music you'll ever hear. Many people will say that longer 'epics' give more time to allow tension to build and such, and while on some level this is true, Thrice has proved again and again that it's not necessary. And then when they do do a comparably longer song such as Deadalus (~ 6 minutes), it ends up being one of the most emotionally moving songs you'll ever hear.
In the end Thrice is a band who's constantly tweaking and experimenting with their sound, but never losing sight of the fact that experimentation alone does not make good music - without a core of good songwriting you'll still have nothing. The result is an incredibly diverse band who's output is consistently incredible and interesting.