Well, you won't - or at least shouldn't - start out again as a red belt, unless you go back to the exact same school as you used to train at, and you might want to have some proof as well (ex. your membership card from the JKA - IF your dojo gave you one...) if they don't remember you, considering you quit ten years ago. You'd be able to advance quicker than a new student nornally would if you decide to pursue a different style, however. There's no real best style for anything... I'd just recommend one of the four original styles of karate if you're aiming for traditional.