Moving my Library from external drives to internal drives?

Up until this point, I've been using two large external drives to store my XBMC library on. I finally saved up the money for a couple 3TB internal drives to take their place, but I'm wondering what the best way to move the library over would be?

I guess if all else fails, I could always just copy everything over, disconnect the external drives, and rebuild the library files using the internal drives, right?