I'm looking for stuff like

Ulver - Kveldssanger
Opeth
Empyrium - Where At Night The Wood Grouse(is that the only album like that?)

Empyrium are just neofolk though. There's a whole genre of people playing that style. One of my favourites is Vali.

http://www.youtube.com/watch?v=MyAUXRapii4

First two albums are metal, if rather on the mellow side. But still with growls.
Edit: I guess that style isn't really called "growls"... shrieks or whatever... more black metal style.

I think you mean with classical guitars as an instrument rather than style? I hear no classical influence in Ulver or Empyrium, and can't talk about Opeth because I don't listen to it, but I'm quite sure you mean something else.

If you're instead looking for neofolk mixed with metal then I recommend you listen to Cadaverous Condition.

Uaral from Chile. Trust me.

Askival's "Eternity" has quite a lot of acoustic guitar work on it that reminds me of Empyrium without the super cheesy vocals.

http://www.youtube.com/watch?v=IAEy3X4cBgM

Ulver does has a baroque influence in their guitars in Vargnatt, Bergtatt and Kveldssanger.

Have you ever heard Empyrium's Weiland? it's classical neofolk from start to finish, not just random nylon guitar passages, but violins, cellos, oboe, flute, grand piano and tenor vocals (Helm is a classically trained tenor who does opera stuff almost every weekend).

Other bands like that are:

October Falls
Vali
Uaral
Tenhi
Musk Ox
Nebelung

If you wanna hear more classical pieces, you can always check Andres Segovia, Agustin Barrios, Narciso Yepes, John Williams, Francisco Tarrega and stuff like that.

If you like more folklorish stuff, look for Quelentaro. It's a chilean duo who develops a unique form of copla. Their lyrics are excellent and the 'tortured' vocals add a very melancholic feeling to the overall experience (the guys are old as fuck and their way to talk and sing carries a lot of sorrow/suffering, these are indeed the main influence of Uaral).

Question about Ulver - Kveldssanger.

Is Joren playing a nylon string on this album? It certainly sounds like it at times. I want to take elements of the style on this album into my own. Is he classically trained, did he study classical? Or did he just write those riffs on the minor and melodic minor scales?

I'm referring to style.

Should I study classical if I want to incorporate it into my style? or should I just listen to it and come up with classically influenced riffs on minor scales?

i think ne obliviscaris

Well, it's pretty much the difference between coming up with halfassed gimmicks and actually knowing what you're doing.

Whats the difference if you know theory?

Although I don't have any experience playing Classical (though that's certainly something I'll work on later) I would recommend a little of both; listen to a lot, then look at the sheet music for a few of the pieces so you know what's going on. You might also want to do a wee bit of research into it as well, but if you know theory that shouldn't be much work.

EDIT: For the original request, I've always thought of Dark Tranquillity's "The Gallery" album to be Classically influenced, but maybe that's just me. Oh, and Unexpect. They pretty much play everything, one song of their's not only incorporated Latin Jazz, but some Polka as well. Their latest, "Fables of the Sleepless Empire" is quite possible the best music I've heard outside of Classical.

Classical or neofolk?

If you want classical then you should listen to Obtained Enslavement's Soulblight and Withcraft. Pensees Nocturnes is fairly good as well. I can't think of any more but you can always listen to Infernus' Gorgoroth, he usually has some classically inspired riffs in his music.

Again, if it's true classical guitar you are after, the first two albums by Norwegian Doom band Funeral ("Tristesse" and "Tragedies") have some lovely classical intros and interludes:

http://www.youtube.com/watch?v=gNNNqQRe6is
http://www.youtube.com/watch?v=2gcVuFh5c00

i think you talk about the acustic guitar, opeth has folk influences as well as classical music influences.
if my concept is right i think you would enjoy Triebgeist acustic sections

Askvial is pretty awesome. Their black metal medievil gimmcik is interesting with its classical styled acoustic riffs. Where could I find tabs for their music?