Paysage d'Hiver is amazing music that's recorded in a way that makes it unappealing to many, but ultimately more rewarding for those who appreciate it. It is better that way.
I also think Empyrium is a criminally underrated band. I think their music is about equally appealing as Agalloch's, but they aren't nearly as well-known and appreciated.
Oh, and their last two albums aren't metal. Weiland also ranks among the best acoustic albums I've listened to.
Twilightning - One of my ffavorite power metal bands. They sound similar to Sonata Arctica and Stratovarius, yet also have more of an 80s sound to them. Delirium Veil has nice catchy songs on it, and the keyboard and guitar work is amazing.
I'd take Blind Guardian over Rhapsody. Someone just posted and said that they were underrated, so I was opposing that point. Rhapsody is definitely very popular in power metal.