He has a case with Finland but I think Nightwish are a bit lightweight, nice to see someone mention Ensiferum, other excellent Finnish bands:
Hail (Black Metal)
Hin Onde (Folk Metal)
Korpiklaani (Folk Metal)
Moonsorrow (Pagan/Folk Metal)
Reverend Bizarre (Doom Metal)
Solitaire (Speed Metal)
Wizzard (Black Heavy Metal)
Norway hasn't had much to shout about recently and is definitely way behind Sweden. For me tho' Germany is the undisputed champion of Heavy Metal at this point in time.