iPodNN | Apple allows album-level iTunes Plus upgrades:

Finally!  I’ve wanted to do this for a while now.  When I was married, my ex & I shared an iTunes Store account so that we could have access to all of the media on all of our devices, as there was some overlap in our tastes.

The key:  some overlap.  I have a LOT of albums in my iTunes library that I have no interest in listening to (Clay Aiken’s Christmas album comes to mind).  I will not pay Apple to upgrade it to the DRM-free version of the files, and I’m not at all interested in playing those songs on any of my other devices.

Now, Apple’s delivered me the option of upgrading just the albums I want.  So screw you, Cher!