Front to back, and back to front. Every time I get a new set of tires, if I criss-cross them, I end up getting weird pulls and vibrations that never go away. Every. Freaking. Time.
Since doing back to front, front to back only for the last few sets of tires, I havent had an issue. Coincidence? Yea probably, but enough to make me paranoid to the point I wont swap sides anymore.