Although I use - and love - the iTunes/iPod combination, it bothers me how Apple continues to be opaque. At a time when a number of companies (including Microsoft, but not, I should add, Google) have made themselves more transparent by opening themselves up via blogging, Apple keeps everything close to their chest.
That's their decision, of course, but it ignores the fact that customers will find ways to talk to you. For example, take a look at this screenshot from iTunes which shows how people are creating iMixes for the sole purpose of letting Apple know which bands they want added to iTunes.
Customers are subverting the iMix feature in order to provide feedback to Apple - feedback which wouldn't even be necessary if Apple just let everyone know that they'd love to offer bands like The Beatles and Led Zeppelin on iTunes, but they're still haggling over the details with the record companies and/or their lawyers.
One way or another, customers will talk to you (and if that fails, they'll talk about you instead).
Update: In the comments for this post, Eric Dolecki points out that Apple has a request music form on their site.