My favourite Finnish bands are Finntroll, Korpiklaani, Ensiferum, Children of Bodom, (old) 69 Eyes (Savage Garden to Blessed Be), ...And Oceans, Impaled Nazarene, Lordi, Nightwish, Eläkeläiset, To Seperate the Flesh From the Bones, (old-mid) Amorphis, Darkwoods My Betrothed, Wintersun, Trio Niskalaukaus, Goathemy, Behexen, Turisas, Horna and Omnium Gatherum*. Okay, on reflection, Trio Niskalaukaus, Amorphis**, Horna, Behexen and ...And Oceans are pretty serious. Nightwish try and come off as being, but they will never live down Elvenpath, especially not the way they're going. Darkwoods My Betrothed are probably trying to be as well but...oh come on.
And seriously, listen to the song 'Devils' by 69 Eyes, if it ain't already plastered over the radio over there. Very similiar, the guitar lines if nothing else.
*I'm aware some of this is pop in Finland. All I can say is, I wish my country had your country's musical taste. Also, Humppa.
**Apart from that Doors cover. LIGHT MYYY FIIIIIRE.
Edit'd because they're not 'Behexem'