Agree with above. Plus my two cents.
I think the 4.10s are a good middle compromise for all around usage. But if you're set on a tire size for sand, mud or highway, now's the time to calculate for good gear/tire combo based on where you want the truck to perform best. For highway, I like the 4.10. You can still pull some weight up a hill, especially if you stay 31 or 29".
Here's another thing you can do after you put in the axles. You can borrow different tire sizes from buddies and stick them on the rear and run it and see if you like where the sweet spot is. Really takes the calculated theory out the decision before you buy tires... tires ain't cheap! Of course once you've owned the truck a while you'll be telling us!
j