#1 on the Tourance
As mentioned by several others, the Metzler Tourance is an outstanding tire. I have one on the rear of my F650 classic with about 5,000 miles on it and I'm expecting AT LEAST maybe another 2k or so. They are a little pricey sometimes, but find a set online and get them sent to you.
I've been very impressed with the grip in the turns as well as the traction in the dirt. After a couple multi-day trips both in dirt and on the slab, I've been pretty happy with them.