Apple has hit a pretty big milestone, announcing today that it's now sold more than 5 billion songs through its iTunes store.

Research from NPD Group has already crowned iTunes the No. 1 U.S. music retailer, eclipsing WalMart in the early months of the year.

Apple also said that iTunes is renting or selling movies on the order of 50,000 a day, declaring itself the world's most popular online video store.

So Apple's got music, it's got movies and it's got the support of the major movie studios (New Line, Universal, Warner Bros., Sony, MGM, Lionsgate).

So what's missing? How about the music labels? For all the talk you hear about how the music industry has learned from its chronic missteps from the early days of Napster, their persistent refusal to deal with Apple makes you wonder how much they've really wised up. (...that and how they're still suing their customers.)

To date, EMI is the only of the big four records labels to license its collection to Apple stripped of digital rights management protection. Sony, Universal and Warner have been unwilling to do so. Instead, they have cast their lot in with Amazon, hoping to break Apple's stranglehold on the market.

To no avail. Five billion and counting.