Not to add anymore fuel to the fire or make you doubt your final selections so far, but I loved the Cooper STTs. I ran them in 285/70/17s. They were great on the highway, relatively quite, fairly light (by comparison at 58lbs) and have an attractive tread pattern (much like the Toyo MT). MPG-wise, I probably got around 16.5-17.5 MPG with the STTs...only 1-1.5 MPG better than with the 285 AT IIs. The were great in the mud and I felt the sidewalls held up to some very sharp rocks. However, I only truly tested them a handful of times so YMMV.
Having said that, there's no exact science beyond the common-sense decisions, AT=mostly Highway or MT=mostly off road, when choosing tires. 10 different people will probably give you 10 different "best" tires. Honestly, I did a ton of research and spent way too much time on the decision IMO. I am extremely (ie..overly) analytical and kept changing my mind so I just said screw it one day and went with my top choice at the time. Currently, I run the AT II, but the switch had nothing to do with the STT in particular. It was more based on MTs in general, me driving more miles each week and, unfortunately, less off road time. Who knows, my next tire may be another MT. :bounce: