What's your mate using? if you're riding similar terrain, similar tyres might be appropriate.
On my 29're I'm using 2.15" Schwalbe Almotion, most of the riding is urban, though they're fine of dry tracks and big enough to absorb some rough stuff. Not sluggish on road, good puncture protection (Or I have so far been lucky), easy on and off my rims, I'll be replacing with the same when they wear out.