Maxxis Bighorn radials are a good tire. NOT the 2.0 version, though. Those are soft.
I have probably about 3k miles on my Bighorns - a mixture of hard road, gravel road, and trail riding. The fronts wear a bit more, but I think I have an alignment issue. I'd say they are about 50% tread still. Very usable.
Get your tires balanced. That should help quite a bit with premature wear.