Like others have said, probably a good vehicle but that price is high.
Some things to check for when you look at it that could be used for bargaining on price:
Timing belt - 90k service
Radiator - might be ok, but they're commonly found leaking when they go in to do the timing belt
CV axle boots - rebooting isn't too hard but if they've been torn for a while then you need new axles (cheap or expensive depending if you choose oreillys crap, OEM, or something in between like CVJ remans)
Rear air bags - expensive to replace with OEM, there are one or two reasonable aftermarket options, or you could lift it and delete the airbags altogether)
Exhaust tick - listen on cold start-up
Dash cracks - they were replacing them for free but it ended earlier this year. Maybe an exception for 2007 but I doubt it.
Nav - not exactly problematic (in fact, I don't recall a single person complaining about a failure) but outdated, virtually impossible to upgrade
CDL - Center Differential Lock. I don't think it's a common issue, but sometimes they get sticky if not used.
There were some small changes throughout the years, like upgraded transfer case supports, adding an aux jack to the stereo, and variable valve timing being added. I think an '07 should have all of those. They seem to be pretty damn reliable, but any older vehicle will require some maintenance. Aftermarket is growing if you're looking for off-road stuff or just general maintenance. Check out the facebook group GX Off-Road (GXOR), as well as the forums at ih8mud, and toyota120.
I bought my '04 with 138k miles last August and paid a little over $12k. I've put about 15k miles on it already, including hitting some passes in CO and a couple hunting/camping trips. I haven't had any reliability issues, but I did spend some money right away to have the timing belt replaced (and radiator, surprise) and then replaced the CVs myself last spring. Plus brakes, diff fluid, etc. Lifted and slightly larger tires, plus replaced the running boards with rock sliders. Just ordered a hidden winch mount with recovery points. Loving it so far!