Well, I see plenty here in Nashville, including a big 2012 Obama on the Prius I parked next to at the YMCA this morning. And I have only seen one Romney sticker in the wild so far. Of course, this being the Red State of Tennessee (thanks be to God) all these Obamaites are wasting their time, money, and bumper space. TN will deliver all its electoral votes to the GOP in November; it will not even be close. Still, it is annoying to see all this Obama crap on display.
I too am seeing fewer Obama bumper stickers this time around. As for stickers for Romney - or any other Republican for that matter - I see very few. But I think there is a very practical reason for that. I don't want my car to be vandalized by rabid Obama supporters.