I'll take smooth blacktop, too--but it's pretty rare around here. If your bike has room for bigger tires, don't neglect that option. I have two very similar frames, Rivendell Atlantis and Rambouillet, and when I built them up I put 700x37 tires on the Atlantis, 700x27s on the Rambo (I weigh 240, so I don't go skinnier than that). I figured I'd use the Rambouillet for most of my riding, just bring the other bike out for fire trails and stuff, but it's become my first choice for nearly all conditions. I run the fatties at 75-80 psi, and it makes a big difference in comfort for a very small tradeoff in speed.