I'm very happy with the Xterra 138k miles and 8.5 years later. All I've done is regular maintenance (including replacing the timing belt at 105k miles.) Occasionally during the last couple of years I've had an itch for something new(er) or different but it's hard to rationalize giving up the X when it performs without complaints, still looks good and feels just as tight as it did at 65k miles. I do need to get an upholstery shop to fix the headliner, but the seats don't show signs of wear after being a daily driver. This is a followup from my review on 05/18/2007 (same user name).
Build quality, the thing is a tank. The seats are still comfortable after 138k miles.
Most of my minor issues have been resolved on the newer models. I wish Nissan would offer a stretched Xterra (the length of the Frontier crew cab.)