I have been running Continental Contact 26*1.75's (45mm) on my LHT for a few years now.

I take dirt roads and paths and fast singletrack wherever I can find them but am probably on paved surfaces 75% of the time at least. Very happy with the ride quality both on and off road. Very comfortable to ride on all day long. I don't really concern myself with speed but I manage to get where I am going and I never feel "too slow". I do have a couple of faster bikes with 23's and 25's on them for comparison.

I have been quite satisfied with the ride quality and performance with the tires inflated to the 55-60 psi recommended on the sidewall. Never thought to run them lower.

Edit: Oh and I haven't had a flat since I put the tires on has to be 5-6k ago miles at least.