Paul, there are some seriously long treads on tire replacement choices for the LR3 in this forum but I will try to sumarize it for you. Nitto Terra Grapplers come in 265 and in 285... /60/18. Most folks find them quite dependable off road and both sizes fit fine on the LR3. I had the 285's on mine for a little while but changed them because they made the LR3 look funny. They seem to be too big for the truck (as far as looks) but I would guess the 265 would've solved that problem. It was my experience with them that they vibrate a bit at speed ( you can see it on the steering wheel ), they cause the truck to feel spongy in corners at speed, and they HUUUMMMMM on the highway. Nothing that can't be corrected with loud music but it drove me crazy. I want performance when I go off road but I want total plush when I'm back on the highway. Which is why I bought Land Rover in the first place, right?
The Good YearSilent Armors also come in 265 and 285... /60/18. They are rated superior to the Nittos in Snow and Ice (though thatshould not matter at all to you in the desert

) and they seem to perform about the same on other off road conditions. The bigest difference is that on highway the Silent Armors are super quiet andsuper stable at high speeds, besides riding extremmely comfortably. It has improved the ride of my LR3 over factory tires 200 fold both on and off road.
There are some other sugestions out there for tires besides the Terra Grapplers and the Silent Armors but after spending countless hours doing research before buying my tires, I found the rest to be either not at all available in the rare sizes needed for the LR3 or too extreme off road (very rough highway ride) or simply all season (useless off road) instead of all terrain. If you intend to turn your LR3 into an off road toy, perhaps the 285's would be better with a higher side wall. However, if like the rest of us you use the LR3 as your daily driver, the 285'sgive upa lotin highway performance, the 265's would do the trick nicely and keep the factory "luxury"look of the truck.
If anyone else out there can think of another serious "All Terrain" tire, not just simply a mild "all season" tire that actually comes available in either 265/60/18 or 285/60/18 beside the Nitto and the Silent Armor,please let us all know. Otherwise, those two seem to be your options in my humble opinion.