Other power bands not mentioned yet you might want to try would be Hammerfall (very martial lyrics, remind me a bit of Maiden), Rhapsody, Gravedigger and Stratovarius. If you think Nightwish's tolkienesque lyrics were bad, Rhapsody are mindblowingly cheesy.
Another one I've been liking recently are Running Wild, an older band with pirate-obsessed lyrics. If you want to branch out a little more, I would recommend Skyclad (English folk-metal), Later Therion ('Classical death metal'. This is no Napalm Death however. Full orchestra and choir on a lot of their later stuff. Their earlier efforts are heavier, and in my opinion still very good, though they may not suit your tastes) and Bathory's 'Viking' albums (Hammerheart, Blood on Ice, Nordland and Nordland II. Their other stuff is mainly black metal)
Hope I've been of some help ^_^
Edit:
@ Roachboy: Indeed, Demonaz, Immortal's guitarist (most black metal artists use stage names) developed arthritis in his left hand in the mid 90's. He stayed on as a songwriter, but the band broke up last year. A pity in my mind, they were one of the all time great black metal bands.