33s are a good mix between DD and trail use. 31 is too small, and 35+ starts to get big for DD. I say 33-34. It depends on the tire really, because most mud tires actually sit a bit higher or lower than the sidewall states. My 33 TSLs sat at 34 inches, and I know the TSL radials (33) sat at about 32 inches. Dont know about other makes.
To be honest, I would drive a truck daily on 44s, but thats cause Im a bit of a redneck.
