Originally Posted by Darth_Firebolt

You CAN go that small, but the ride will be harsh and you'll probably get more flats. I would say at your size not to go much smaller than 1.75, especially if you're worried about your wheels taking a beating.

Originally Posted by Wilfred Laurier

I concur. There is very little advantage in using narrower tires.

If you do want to use narrower tires, though, that is your choice. The only general rule of thumb is avoid tires narrower than your rims, so that likely means 1.5" or more.

Originally Posted by slowride454

if you are dead set on skinnier tires then a set of quality 26x1.75 like these would work well
Schwalbe Marathon Plus Tour Tire > Components > Wheels, Tires and Tubes > Tires | Jenson USA

Personally I like big tires and if your frame can fit them, I'd get these
Schwalbe Big Apple 26" Tire > Components > Wheels, Tires and Tubes > Tires | Jenson USA