Judging by the PPM markets out so far it looks like Spanish language and Urban/Hip-Hop take the biggest hits. The extent of the loss varies from market to market but the trend is clear. Based on that I'll predict that KISF will have the single largest drop of any station diary to PPM. Looking at the LA PRECIOSA station in San Jose (KSJO), KWID could be in for a big drop as well. Being the most urban sounding of the rhythmics, I will guess KVEG will also go down with PPM. I know that Arbitron is getting a lot of pressure about this, so maybe by the time the first PPM numbers come out in LV the ethnic stations won't take such a big hit?
As far as lower rated stations moving up. Maybe KXTE? I'm sure they are waiting to see how they do with PPM. In some markets Alternative thrives with PPM, check out WRFF in Philly! Although they have a softer blend of music than EXTREME does. On the other hand there are other ALT stations that did poor with the diary and continue to do bad with PPM (WKQX/Chicago, KITS/San Francisco, KDGE/Dallas).
The country stations might go up with PPM. The country station in LA KKGO is doing a lot better with PPM, but that's on the surface 6+. I read (just like country in Las Vegas) that the demos are old, GO COUNTRY ranks poorly 25-54. It's interesting how in some markets like Dallas country clearly benefited with PPM while in Houston the format did not rebound, look at KILT in particular.
I also predict with PPM some of the strong will get even stronger. I expect KSNE to be HUGE with PPM. FRESH being gone will help SUNNY all the more. I heard FRESH in quite a few business's, they would have gotten a PPM boost, now it will add to KSNEs already large share, MIX will benefit too. Another station that does well now that I think will do even better with PPM is KKLZ. Classic Hits (I'm sorry "Greatest Hits") does excellent with PPM!