They cost less than a new bike and the best all-round for road and normal trails whilst offering extreme puncture resistance:
http://www.bikeradar.com/gear/catego...supreme--31009
The alternative is to line your tyres something one of the experts on this forum swears by (Jur). However I have the above on one of my bikes and boy they deserve their 5 star rating! I use them on off-road and on-road and they came as stock tyres on my Dahon Jetstream EX which is designed for trails.