Nightwish, One of my all time favourite bands. Unfortunately I wasn't so impressed with last album (even thought I love songs like Yours is an Empty Hope, Shuder before the Beautiful or even The Greatest Show on Earth)
Arch Enemy has legendary guitarist Michael Amott from Carcass. It is one of the few metal bands with a female vocalist. They are getting more popular with each album, and every one is getting more melodic than the last.