I have owned my Nissan Xterra since I bought it new in 2000. I have not had any problems at all mechanically. I have the oil changed every 3000 to 5000 miles. The only thing that has been replaced a couple of times has been the battery. Other than that it has been a great vehicle. I am even thinking about buying a 2008 or 2009 when I'm ready to buy another vehicle. I've been totally happy with my Xterra the past 8 years. I have read that some people have had problems with rust forming on the exterior. I noticed some rust that appeared to form in the paint but with occasional waxing it inhibited any corrosion. Overall the best vehicle I've owned.
Good looking design. Utility is endless. What ever you can think of, you can use this SUV for. Except for hauling big stuff, it can do it all.
Better fuel economy. Other than that can't think of anything that needs improving.