Whenever I have to reinstall iTunes, I also have to reapply the hacks that make it behave the way I like. Mostly for my own convenience, here is a list of the hacks I use.
To get rid of the Ping drop down menus next to artists and so forth, type this in Terminal:
To enable half stars in track and album ratings:
To restore the little store link arrows removed when Ping was introduced:
And to make the store link arrows filter the library rather than launch the store: