I like the Maxxis Desert IT. It's cheap, gives good traction, and lasts forever. It's really hard to beat.
For Arizona the Desert IT does wear well, probably twice as long as the normal IT. But the traction isn't as good as the regular IT. I've been stuck more than once on hill climbs (using the Desert) that were never a problem on softer IT.
If you change tires a couple times a year, go with the Desert IT, 606, or 739AT. But if you change tires frequently and like a fresh, grippy, and cheap tire ($40) go with the normal IT.