PC-to-DAC advantages: you have access to your entire library at one time, not just what's on your iPod. You can save some money not having to buy a digital iPod dock. Setup might be a bit more complicated, but if you are a computer oriented guy, and are willing to tweak a bit, you can get better sound quality for less money.
iPod-to-DAC advantages: If you are completely iPod based, i.e. you use it in the car, at work, at the gym, this could actually simplify your life a little, compared to the PC route. A decent USB/SPDIF converter will still imporove the sound coming off of a digital iPod dock, so if you go PC audio first, then get a dock, money spent on the V-link (or other) is not lost.
one thing that bothers me about the iPod route is that the docks all come with remotes, but the iPod screen is so small, you'd have to get really close to it to see what you are browsing. PC laptop screens are bigger!
sound quality will be dependent upon the clocking of the digital signal and the DAC. Generally it is not a good idea to go analog out of a digital iPod dock or a PC sound card. Get a good DAC that re-clocks the incoming signal (asynchronous), or use a USB/SPDIF converter (Vlink, Audiophilleo, Anedio, Stello, Jkenny, dare I say Empirical Audio...?!?)