I am guessing 255/85/16's or 285/75/16's just depends on if you want tall\skinny or taller\wide.
Don't be afraid to put a little lift on it, a set of add-a-leafs on the front and blocks in the rear will look great with bigger tires. The stock aluminum wheels are very narrow, I would go tall\skinny to stay on the safe side and have good tire wear.