Sedona Arizona. I've been to this city twice now and each time I visited it was a unique experience.
This first picture really sums up the best parts of Sedona for me: red rocks, vibrant green trees, and a well setup Jeep.
There are several great off-road trails within a quick drive of Sedona. A few of my favorites:
Broken Arrow Trail - Definitely top of the list. Its right at the Southern edge of the city and is one of the more technically challenging trails in the area. Its a very popular trail so expect to see lots of other off roaders, but going at night you will find it secluded and it offers a great view of the city lights.
Solder Pass Trail - You need to get a permit for this trail in advance but its well worth the extra effort. It's another trail located close to town, but the rocks and scenery make it feel like you are miles away. Its a moderately difficult trail, but with a high clearance vehicle and good tires you should have no great difficulty. Its a very popular trail for hikers so be sure to watch for people while you are off-roading.
Diamondback Gulch - One heck of a hill climb. It takes a while to get back there and you are driving along a old wagon trail the whole time. Additionally, on the trail you can pass by the setting for the John Wayne movie "Angel and the Badman". Don't expect to see many people back there, which is great cause you can climb and descend the hill as many times as you want and not have to worry about lines. Definitely one to visit.