I mostly have been using Conti Gatorskins. They ride OK except on chip seal which is rough. This summer I've been riding a 28mm Specialized Turbo Pro on the back wheel which is smoother than the Gatorskin. At about 1500 miles the tire has visible wear but barely so. I can see getting another 1500 to 2000 miles out of it. This tire is mounted on a Velocity A23 rim and measures 29.5 mm. If this tire seems a bit too plump, they also have a 26mm tire. I don't have the 26 mm tire in hand but when I do, it will go on the front wheel that currently has a 25 mm Gatorskin. I think the Turbo Pro is a fine combination of smooth riding and long wear.
https://www.basinski.com/shop/specia...FRJbhgodGq4O5A