I pretty much exclusively run touring tyres on my MTB. I've recently swapped from Vredestein Spiders which are nice fast 1.95 semi-slicks to Schwalbe Marathon Plus (1.7) which are very fast rolling, should be nigh on puncture proof but are heavy. I liked the plain Nimbus - it's an okay tyre but found the Armadillo version lacking suppleness and spring - okay on very smooth tarmac but on rough tarmac...