If you aren't too worried about gas mileage, then it's a good truck for you. They're very durable and quite offroad capable right out of the box. Main thing to look out for on older Xterras is their exhaust manifolds are cracked and out of warranty. Do a search and you can find out all about that stuff. Other than that they keep on running.
You can find lots of good deals on the older ones as people are dumping them with gas prices so high (well almost any SUV really).