I'm one to use somewhat non-traditional wood combinations. I have made necks from Peruvian Walnut, Koa, various Rosewoods, Black Walnut, etc. Some of my best necks have been Peruvian Walnut which has a very straight grain when compared to Black Walnut etc. Koa is by far my favorite. I wish I would have purchased a lot of it before the prices skyrocketed. Granted Koa is in the mahogany vein but it has some qualities that I haven't found in other close relatives. Even when it comes to bodies I use a variety of woods that aren't in the tradition of guitar building. Different is good!