I have Cooper Discoverer S/T's on my truck. They do great in mud/snow, and pretty good on wet roads. They do make a lot of noise but I kind of like that, sometimes I turn the radio down just to hear it.

I also have had BFG all terrains, pretty decent tire. And for a cheapie tire, Regul makes one called the trailblazer which I have also had, they did great as far as tire wear and traction and were only 70 a tire but that was at cost for the tire store I use. As far as the 18" wheel size, can't help you to much there.