PC Audio Choice: Mac+USB, Transporter, or Squeezbx

Hello all of you who have faced choosing your path for PC audio!

While I have a Mac Ibook G3, 500gb HD and Paradisea USB DAC on my second system, I am wanting to ultimately have PC audio available on all 3 systems in my house, or atleast the two that I listen to most. I am trying to decide what path to take. For the main system, do I:

1) Buy another computer, dublicate my 500gb HD and run itunes seperately from that, using a good USB DAC or a USB converter to a conventional DAC.

2) Buy a network HD and a Transporter, possibly with a Modright Truth mod (this is really more money than I want to spend...)

3) Ditto to the above but use a Squeezebox with various add ons, such as antijitter filter and a good DAC.

I guess what I'm asking is, which of these options presents the best bang for the buck? Also, which is most flexible with respect to listening to content available on the internet (e.g. archives of live Grateful Dead concerts, other streaming and non-streaming content). Finally, are there any limitations to high resolution when using any of these - as I imagine there will be more and more high rez downloads available.

Thanks for your opinions. Please provide the basis for your thoughts! Thanks, Peter