BF Goodrich All Terrain KO 225/70 x 16
$225 each fitted and balanced

BFG AT close

BFG AT tread

Bigger tyres (or wheels) are the only thing that will lift the diffs so you gain in all ways;
235/60 x 16 (standard) = 688mm (27.1 inches) diameter
225/70 = 721 (28.4) - ie this tyre will lift your diff 16mm (0.65 inch) higher than standard
225/75 = 744 (29.3)
235/70 = 735 (29.0)
235/85 = (31.8)
245/70 = 749 (29.5)
245/75 = 774 (30.5)
These are the sizes that BFG AT come in

According to the Yahoo mailing list a 225/70 is the biggest tyre that will fit on a standard GV.
After I get my 2 inch lift I will fit a larger tyre. I am tending towards 235/70

Be aware that any tyre that is more than 15mm larger in diameter than the largest standard tyre strictly speaking requires an engineers certificate (in NSW, Australia). Larger tyres will make your gearing slightly higher. Also, a bigger tyre will make your speedo read low so borrow a friends GPSr and check how far it is out before one of the speed cameras does !

Tyre pressures;
On road I run 35 PSI
For good dirt roads where I will shortly be back on bitumen I run 24 PSI
For dirt trails and general 4WDing (including mud) I run 18 PSI
For sand I run 12 PSI
with 225/70 BFG AT above (at 30 psi) but otherwise standard
(half tank of petrol, normal tools in drawer, no occupants)
Front - bar just behind diff - 22.0 cm
Rear - diff drain plug - 21.5 cm
Standard clearance 20.0 cm
Frame rails - 23.2 cm at front to 24.7 cm at rear

Tyre size calculator