3rd person with diff. fluid suggestion, that's my job for this weekend. Tires are great, so don't think its that but that was my first thought when I noticed it. What do I look for with drive-shaft and u-joint issues and axle/wheel bearings?
Look for dents or even a minor ding in the driveshaft. You can put the car up on stands and run it in gear and see if the driveshaft is bent. If you unbolt the driveshaft you can see if either of the u-joints are binding.
