I might go with some slightly odd choices here:
Jariot Lehtinen from the band
Waltari.

The guitarist everyone knows from that band is probably Sami Yli-Sirniƶ since he has played in Barren Earth and currently in Kreator as well.
Sami is great and all, but my favorite was always Jariot. He's plays very soulfully and I love his guitar tone. Go to 02:59 for a good example:
Pekka Olkkonen from the band
Stam1na.

He writes almost all of the music in what is one of my top 3 metal bands in the world, so how could I not pick him? He plays all the solos as well and I love his style. Check out the whole section from 01:37 to 02:51 to see what's so special about this guy:
Kaoru from the band
Dir En Grey.

Inventive, skilled, stylistically varied and a guitarist with a very recognizable expressiveness to his playing. So many great riffs, so many fantastic solos, so many interesting details in his guitar playing. Check out the section starting at 02:30 for an "argument" as to why this guy is top level material: