Is this a question for what I like to hear during pokémons battles, or whatever (Like fighting a boss in any other game, for example.) Because if it's the latter, I shall move this :T
Anyway, for pokémon battles, I just turn this on and go with the flow. Fits every single battle ever.
If we're just talking about fights in general, then this will suffice. Either that or I just turn on a playlist and keep it rolling when I'm fighting bosses that can take a while, like in Dark Souls.