I'd like to know which scales are used by following bands:

ENSIFERUM

...and also:
Wintersun
Summoning
Burzum
Therion

I appreciate any information.

Well the scale of Guardians Of Fate is something like this:

|-------------------------------|
|-------------------------------|
|-------------------------------|
|--------------0-2-------------|
|-------0-2-4------------------|
|0-2-4-------------------------|

__________________

You can almost bet any melodic metal band is going to utilize the 7 modes. Most common is the natural minor (Aeolian).

__________________

Varg actually composes through the conscious use of scales? Doesn't sound like Ol Vikernes to me so much. . . . he seems more of a "I'll go with what I think sounds cool" especially since he is not very melodic in his writings. Not downing Burzum, I own every CD, but the thing is, he is what he is meant to be, pure raw metal material recorded through a basement filled with lots of anger and hatred. Summoning are semi melodic though but they use a lot of natural minor, as Davie said. As for Wintersun, same guitarist as Ensiferum except he goes all out with the downtuning and two step bends for solos such as the one on "Death and the Healing." If you haven't you should definitely check out Ulver as well though. . . harmonic minor(natural minor with a # 7) is also very prominent in melodic metal, they utilize it more as a lead thing than a rhythm thing though. . . .sounds good.

__________________