The whole lack of digital audio output is a major let down. My entire system is hooked up with digital audio, including satellite, DVD, X-Box, and PS2. The only thing that's missing is the Gamecube. Hence, when using the Gamecube I have to tell the stereo to switch back to using the input in analog mode, which is quite irritating (especially if I forget to switch it back afterwards!).
Even though the system lacks Dolby Digital, it still would have been nice to just get the two-channel PCM audio in digital format. Maybe Nintendo could have contracted such a cable out to Monster? Oh well.