HP's goal is to bring the most compelling entertainment content and experiences to our customers, ... We explored a range of alternatives to deliver a great digital music experience and concluded Apple's iPod music player and iTunes music service were the best by far. By partnering with Apple, we have the opportunity to add value by integrating the world's best digital music offering into HP's larger digital entertainment system strategy.
From Joint Apple / HP press release dated 1 January 2004 available here.