I've been quite happy with Pre/Mac syncing using Google and MobileMe. It has been working like a charm.

But last night I noticed that a new entry in my Pre had not made it to my address book on the Mac. I synced the Pre, then the Mac, but still nothing. After scratching my head a bit I opened address book preferences on the Mac and "Sync with Google" was unchecked. No way was I in there for anything since I originally set it up to sync with Google. Rechecked it and all is well again.