Sure watching anime is fun in itself and often looked down upon by some. But it is an excellent tool to discover some very nice quality music. 
Some anime's even include superb metal(ish) music. Thats why i chose Fairy Tail's soundtrack('s) as inspiration for this SL. 

 Background music for anime series and series in general is often fitting but rarely is a full production on its own. the guy's behind Fairy Tail raise the bar dramaticly in this field of motion picture soundtracks. This music draws heavily from the Metal world. With good riffs, rattling drums, use of synths, violins, soprano's and irish or general folk instruments. Infact they released 5 albums full of excellent music covering the full spectrum of emotions. Often energising battlemusic or heartbreaking sad music. The Music is composed by Yasuharu Takanashi and released under the Pony Canyon Label. You can look up the trackists on Wikipedia. 

When you hear the music as part of the Anime, it is already very awesome and engaging. But the full power comes out listening to the full tracks. Just set aside your love or hate for Anime's. And let yourself be carried away to a world of magic and epic Celtic inspired tunes. 

Below is a Compilation of some of the finest battle songs from all the released music. If you want to find more just search youtube for Fairy Tail OST. You'll find indivitual songs as much as other compilations and playlists.