The best road tyres IMO are Michelin Pilot Road 2CT. Grippy enough in the dry to allow full lean, excellent in the rain and good life too - currently up to 6000 miles on the ER6 with another 3-4k left in them.
Not quite as sticky as Pilot Power 2CT, but not so that you'd notice. The latter are great too - took me to a 4th place in the rain when my wets failed to turn up
I rate both tyres leagues ahead of Diablos.