I vote metzeler z6, same as the pirelli diablo strada, but little more meat on it, and better water handling. Plus NEW version is coming out in 2009, and might get them for cheap in the next upcomming months.
But i have 2k highway miles in mid summer heat, couple loops on the dragon, and many many local roads. many highway wet, really wet commutes home on the interstate at 70 mph, tires have acted flawless, never felt a bit of a slide or loss of traction. still have the round profile.