It's pretty easy to tell where iTunes makes the bulk of its money based on how it responds when you try disabling some of the media preferences.

Hop into your iTunes preferences and start unchecking media sources, you'll find that some uncheck without a fight while others throw up messages like this:

and this:

Outside of those two, you can turn off any of the other options without a fight. Wonder why that is? The other ones provide access to free content. No money in Apple's pocket means it can be hidden without a fuss.

Okay, so maybe it isn't quite that cut and dry. They do make money on games and ringtones, but I get the feeling that they don't see this as a big enough business today to force on people.

The one you can't turn off no matter what is Music. Even if you only use iTunes to download podcasts or watch movies, you have no choice but to be constantly reminded that you're not using iTunes they way Apple decided you should.

This is how I roll:

Podcasts, then radio and music would be how I'd rank my iTunes listening preferences. I've also switched to Amazon as my first choice for buying music, so the default version of the iTunes Music store isn't exactly helpful either.