Yet another vote for Primo Racers. If my bike had enuf room to run 26x1.25's with fenders (d**n those 650c highracers anyway), that'd be my tire of choice. Fast, smooth, good cornering, durable and cheap. Doesn't get much better in my book.
As it is I'm stuck with Conti Gatorskins (faster but not quite as smooth-riding) or Schwalbe Stelvios (harsher riding, slower and more expensive).
SP