Onkyo has announced a new product that is an external DAC for the computer connected via USB port. I think retail is a few hundred bucks, so it's not exactly cheap, but it's a step in the right direction as far as connectivity of a computer and a good sounding audio system.
Another possibility is the Lansonic "player". It connects to a computer via ethernet cabling, and is made to feed a high-quality audio system via analog connections. You can buy it with harddrive storage or plain jane and just use it as a DAC. You can control it from and browser connected to the network.
I keep wondering why it's taking so long for audio manufacturers to come up with these convergence products, as I have to believe there's a demand for them. Maybe not from die-hard audiophiles, but certainly from a lot of music lovers. -Kirk