I had good experience with Michelin tyres. Depending on your terrain and style you can combo Wild Rock'r/ Wild Grip'r/Wild Race'r tires as you need. Continental makes also good combos. Mountain King front/ X-King rear or X-king f/r setups are quite popular where I live. Or you can experiment with less common brands like WTB or Geax.
There are so many possibilities... you only need to pick one and see if it suits your needs.
I'm a huge fan of wider tires since you can run them at lower pressures. I have a 2.5 nevgal in front and 2.1 in back. Soon that 2.1 will be a 2.3 though. Ive found the lower pressure give me more traction and a much smoother ride.
Wild Rock'r, Nevegal and Mountain King? 2.5" - 2.3"? ..did you guys notice the "XC" in the original post and thread title?
I like the Geax Saguaro for XC riding as it rolls fast, grips well (relative to other hardpack tires) and wears very slowly. It's available in 29 and 26 x 2.2 and 2.0. If you have a lot of rocks you can use the 2.2 in the rear. Otherwise, I'd use 2.0 at both ends or 2.2 up front if you just prefer that.