I have two wheelsets for my crosscheck- one with 25mm gatorskins and the other (outside of cross season) with 40mm Vittoria Randonneurs. The 40mm tire adds a few minutes to my 40 minute commute, but is infinitely more comfortable and fun to ride than the 25mm. I even did a 300 mile tour this summer (grand canyon, zion np and bryce canyon) on the 40mm randonneurs with no problem. 65/70psi.

i will note that the 40mm randonneurs are large for their size. i've been having trouble finding fenders that will fit over them in my cc frame, but it's definitely doable.