I have one of the older Chromoly frame MB's, not super light but comfortable. For years I road on 2.1" CitySlickers, which worked well on rough road, cobblestones, potholes and bike paths. Skinny tires would not have done as well. These days I've got 1.5" WTB Slickasaurus tires which are good for 1.5" tires but for off pavement a bit more surface contact would be better. Reviews aren't great, lots of flats mentioned. For off pavement I need something better.

I'm eyeing the Serfas Drifter City Tire which comes in both 1.5 and 2.0 inch widths. Looks like a good tire for the road with its high smooth center but also capable of handling rough. I will probably go back to the 2.0" width, very versatile.

Another option is the Continental Travel Contact Tire, smooth center which can also handle varied conditions. Lots of good options.