If you want to purchase any accessories (hitch, rack, mud flaps, etc.) you may want to ask if they will be covered by the factory warranty if you add them at time of purchase. When buying new, if you add that stuff and have the dealer install it...it is covered with the rest of your car. If you add them yourself, no dice.
If you want to talk in any freebies into the sale, in addition to bargaining for an extended warranty, you could ask for the most recent Navigation map, and I find the loadspace mat very useful. It is a soft rubber mat that covers everything behind the rear seat. And floor mats of course.
When you buy it they'll probably check all SW for the recent updates and TSBs. Take it out for a drive, come to a coasting stop, hit the gas...make sure the car doesn't lurch forward (slam into gear un-natrually). If it does, there is a tranny SW update you need. (discussed here). That is something about a premature downshift when you come to a coasting stop. SW fix takes care of it. I think that problem was in '06s as well. I know I had it on my '05.
See how much brake life you have left. It is easy to peek at the pads. Some people have complained of early brake wear. If they're going, you may want to get the brakes done prior to purchase.
Good call on the tires. I'd also ask them to check the alignment before you drive it off the lot. That seems to go out quickly and I think the alignment specs have changed since the initial '06 release. Something I read on here. Anyway, start fresh!
That's all that comes to mind. 29K for a low mileage LR3 is a great deal! Enjoy it.