Honestly the best thing for serious offroading is a locker. It all depends on what you need. LSD's are totally useless in my mind, just from my experience offroad, which is mainly with jeeps, but worthwhile nevertheless.
Lockers are the best for serious stuff. Few pieces of advice, I've good experiences with a quality electronic locker, some people may say otherwise, but mine never once failed me. I have, however, watched ARB air lockers blow on several occasions. If you decide on a true locker, what ever you do, DO NOT get a "full-time" locker. Make sure it is selectable.
"Do, or do not. There is no try."
Wise words, from a wise muppet.
2008 Toyota Tundra SR5 Double Cab 4x4
33"x10.5" R18 Toyo Open Country M/T
20% Tint front/15% Rear
Leer 100R Camper Shell
DDM HiD 35w 5k headlights
Weathertech window visors
Weathertech front floor mats
Husky rear floor mats
XM Satellite radio
Soon to come:
Bushwacker pocket flares
Full metal front bumper/winch