The Pagan Front is a interesting website about many different bands playing National Socialist Black Metal. Not only does this site have reviews, but also articles by some musicians.

This website is exclusively about Swedish bands playing every kind of metal.

Sorry, but this excellent website is all in Russian. For those who know Russian, this website has very good stuff, especially it's big section about many different bands

Metal Centre is a Polish website in English which, even thought it mostly is about Polish bands, has interesting stuff.

Metal Rules is one of my favorite metal music websites. Not only does it have the usual reviews and band interviews, but also monthly movie reviews (from a metalhead point of view!), articles on music, even a "Are you Metal Or Not?" section, where other metalheads rate your "metalness," and decide whether you are a true metalhead or just a poseur...