When someone asks for the "best" AT tire my response is almost always the BFG All-Terrain A/T KO2. They have been the standard that all AT tires have been measured against for 50 years.
However, BFG KO2's are pricey and the trade-off for their reputation as a long lasting tire is that the rubber compound tends to get hard as they wear/age. Still, they are better at more things than other AT tires.
Based upon OP's parameters, my recommendation for an excellent general purpose AT tire at a slightly lower price point would be the Cooper Discoverer AT3 LT series. These tires perform well in almost all conditions, are reasonably priced, and last a long time. I purchased a set for a 4,100 mile overlanding trip in my Xterra that I completed in January of this year and have zero regrets.
My Cooper Discoverer AT3 tires replaced a set of Cooper Discoverer ST/Maxx of the same size. These have a more aggressive tread than the AT3 and have 3-ply sidewalls. They are a well performing tire that stands up to abuse, but they are stiffer and heavier than the AT3. I got 45,000 miles from mine and still had some left. In some ways I like them better than the AT3. Which to choose really depends on personal preference. If you need tough sidewalls this is the tire. If a smooth highway ride is the priority then the AT3 would get my nod.
Another great alternative is the Mickey Thompson Baja ATZ-P3. Cooper Tire owns Mickey Thompson and the Baja ATZ-P3 has the same tough 3-ply sidewalls as the ST/Maxx and STT/Pro. The tread might be best described as in between the AT3 and ST/Maxx in terms of aggressiveness. I have a set on my LJ. I like mine very much, although for my uses I may switch to the STT/Pro or ST/Maxx for my next set of tires.
