I've been on Panaracer XC Fire Pros 2.1s for around 5 years. Love the tread pattern for everything but really wet mud, but I dont ride often in the mud unless its snowmo trails or farm roads.I am thinking of moving to something meatier.
Specialized The Captains seem to be a solid choice in the midwest. I see them just about everywhere and everyone is happy with them. I even owned a pair myself for a brief while and they where as expected a great tire. I now run a set of Maxxis Ikons 3C EXO and sometimes put a fat front with a Nate on.
I was running Kenda SB-8s both front and back, and I recently switched to a pair of H-Factors.
I have to say, both have strong points... I really like the roll of the SB8s on hardpack and most roots/rocks but hated them on off angle rocks and even moist soil. The H-factors are much more stable in turns, and are noticeably slower but still ok for how I ride.