I think I'm going with 275/70R18. It's one size up in height from what I have already, but almost the same width. I'm using factory wheels.
It's definitely a mud tire, but the reality is that clay mud is the most common obstacle I will face off road in my area. No rocky mountain trails, sand dunes, or deep snow in my area of the deep South.
People seem to have high regard for the Cooper brand of tires overall. Lots of guys have told me the STT Pro is great offroad, but noisy and heavier than I want to go. I've only gotten a couple of first hand reviews of the Evolution.
Thanks