This is a question that I am also currently seeking but have done extensive research. I've read all the blogs (at least I think). I've called all the companies especially with rumor about new tires coming out (Pirelli, Nitto, etc.).
I am swapping my 19 wheels for 18 wheels and plan to (next week) purchase the Nitto Terra Grappler 265/65/18. Last week I planned to do the 285/60/18 as you are thinking. As far as I can read, both tires fit per other people. Again, I don't have experience personally but am about to do the same thing.
My dealer believes the 265/65/18 is a safer bet as he has them himself. One person at a dealership was concerned about the 285 rubbing against a compressor line; however, there is much more literature (including the excellent blog that was referenced) about the 285/60/18 being a perfect fit with no scrubbing even with max articulation.
Thus, I think the call will be up to you...I am personally going to go with the 265/65/18. I think the slight height advantage will be better for me than 20 mm width. Good luck!
-Josh