Are the tires that came with the Xterra from Nissan good for off-road? I read that all terrain or LT tires are good for off-road driving but the passenger tires are not. Your advise is greatly appreciated.

I'm not quite sure what you're talking about, you're mixing some terms. "LT" vs. "passenger" could mean the difference between the same brand/model P265/70R15 and an 265/70R15LT tire, which are the same size, but have different construction, strength, load rating, and pressure requirements. The P type is better suited to lighter-duty use, while the LT type is generally tougher. If you're looking to wheel, get the LT type (or a floatation type like a 31x10.50R15).

All-terrain is another thing entirely, referring to the tread pattern of the tire. Of course an all-terrain is going to do better off-road than your stock all-season type tires, and most all-terrain tires are LT or floatation type as well.

Most any all-terrain you'll find will still have very good on-road manners as far as traction and handling, but may not offer as smooth a ride. Unless you get a tire with too high a load rating (C, not D or E), they should still give a decent ride though.

As for your choices in tires and sizes, don't think there's much that hasn't already been said here, read up on previous discussions.

Brent