With PPM, cume will become much more valuable (and most all stations will have more of it). Once PPM is in enough markets we will see (or should see) a resurgance of oldies radio and more talkradio (unless this Fairness Doctrine crap comes back). Older folks are still listening to the radio, so stations that cater to that group will do well. Kiddy formats like top-40 aren't doing as well because - you guessed it - fewer kids are listening to the radio. So don't expect Pro-FM to benefit unless they have morphed into an AC of some sort.
Christmas formats have been HUGE in PPM markets, so expect to see that craziness continue. Also jock chatter is a big tune out factor, not surprisingly, so most PDs will have their staffs keeping the breaks tighter and tighter.
But the best part is that for once the ratings data will be ACCURATE! No more writing down whatever you want, like John DePetro's "listeners" did. That will hurt heritage stations that have relied on their brand power and not their programming.