If language is not a barrier, I'd probably go to: Finland, Norway, Denmark, Sweden, or The Netherlands. Basically good quality of life index (education, healthcare, women's rights, etc.), social democracies, gorgeous nature (for the Scandinavian ones anyway) and vibrant metal scenes.
If I'm feeling lazy about learning a new language, I'd probably favour the UK or the francophone countries, such as Belgium, France or Switzerland, however, I've heard it's notoriously difficult to emigrate to Switzerland.
Recently moved from Australia to London, getting to see a ton of metal gigs is a huge bonus. Berlin is very tempting though, just as interesting and the cost of living there is much less..