I'm really excited for some of these Attack Speed items

Statikk Shiv Phantom Dancer Rapid Firecannon Runaan's Hurricane

There's so much variety now instead of just Shiv or Phantom Dancer. I'm assuming Kalista and possibly Ashe will build Runaan's, all of the 500 range ADCs will benefit a lot from Phantom Dancer. Tristana, Cait, Jinx and MF will probably go well with Firecannon. (I'm excited to see MF's Love Top + Firecannon) And Shiv is still there for people that need a little extra waveclear.