I would really love an outboard automatic room correction system like TaCT. Something that goes between the processor and amplifier. But I don't really expect that to be something that can come down the pipeline at a reasonable price anytime soon. I'm thinking ~$500/channel at most. XLR inputs and outputs, in addition to RCA. I suppose it would have to have really good ADA conversion, otherwise you've just defeated your processor's DACs. If it could take digital LPCM signals, that'd be amazing, but extremely unlikely. Maybe good use of the Firewire port on the DMC-1 though.
Other than that, the Reference 4 and Reference 200 speakers.