It all comes down to how much offroading you are going to do..
And then what sort of offroad driving you are going to do..
If Sand, then an allterrain with lowered pressurs is fine, I personally prefer the BFG's and i think if you do alot of offroad is important to stick with quality so you dont wreck them and get caught out on a trip. The bfg's ar the most widly available tyre also.
If rock then a good rock tyre compound namly the Goodyear MTR (maximum traction radial, often mistaken to be mud terrains) is a great tyre
In the Mud, then Simex Centrepedes are unbeatable!!! However Pro Comp, Mickey Thompson MTZ's and the BFG Muds are good tyres..
Im A big fan of the MTZ's They are a GREAT Mud and rock tyre, with 8 ply sidewalls and have decent on road charactoristics!
You can always step up to IROC's or Swampers or Boggers or Baja's however these are offroad only tyres, designed to be run with beadlocks and at VERY low pressures.