At least 3 if ya love it, can look for a cordinating neutral for the back later. My opinion :)
Depends what type of projects your doing, Pick one and go your taste for certain things will more than likely change, as you go, enjoy the process ( reminding myself of this now that have one going that I'm growling at :) LOL) but will be pretty whan it's done.
Good luck and Happy Quilting, Welcome