Hi Jeffrey,
The trip Osaka - Tokyo pretty much pays for the 7 day JR Pass, so any additional travel you may do with it is basically free. For instance you could visit Kyoto / Kobe or Nara from Osaka as a day trip, all make for great visits. If you feel a little more adventures you could hop on the Bullet train and visit Hiroshima.
An other popular visit from Osaka is mount Koya, this area as very beautiful but not covered by the JR Pass so you could visit this outside of your JR Pass period.
Lastly if you would like to try an Onsen, you could head up to historic onsen town of Kinosaki, this is north of Osaka. You can visit it as a day trip although I think that you get the best experience if you also stay for a night in one of the local Ryokan.
Hope this helps!
Daniel