Haven't noticed any drop from my sites. I'll double check when I get home though. Since when did you notice your drop? Might be the start of another PR update as early as now.
I think Google is going through a big update.. It is updating images, rankings for almost all keywords.. My site which was on first page from 4 or 5 months, Is now dancing, sometimes it goes to nd page then again come to first. Don't know what is going with Google.
Well, there is no update in PR but certainly something is wrong with google as i lost my position in SERP for my major keywords. And i have seen few more people loosing their SERP rankings. I hope it become stable soon.
I can confirm serp changes (for the good on my part). Lately I've seen some sites ranking who were spamming their keywords in their title tag (like 3 times). It looks like the ones I've been following took a minor hit. No PR Changes for me, but I see alot of my new pages went from "n/a" to "0"