That Eric Whitacre link was great, thats one added to my next shopping list!
(edit: well, if/when its released anyway, but I may order some of his other albums)
The Cruxshadows. I only dicovered them a year or so ago when someone recommended Ethernaut to me, and then I found Dreamcypher which IMO is one of the best albums I've listend to in years. Some of those genres listed above are ones I know nothing about but based on the recommendatiosn they are grouped with, I'd be interested in some recommendations of specific artists from them.
Now a few more recommendations of my own - trying to find stuff in my collection I don't think others have recommended yet (but I'll go ahead and throw in recommendations for Arcana, Flogging Molly, Enya and Clannad). (a slightly trimmed down version of my music bookmarks webpage)
Folk/World (Neo-Folk, Folk Metal and other Medievalish/Reniasance sounding stuff)
The Soil Bleeds Black
All My Faith Lost
Echoes of Eternity
Visions Of Atlantis
And a few I don't have links for (may or may not have web pages or myspace samples)
3rd and the Mortal
Angels of Venice
Arise From Thorns
The Ink Spots
Storm (Folk metal band that only released one album, hard to find)