Wait... why not keep the powerbook in the chain.. you are by now used to browsing your music via iTunes... right? External USB hard drive, and rip those CDs in apple lossless. Then get a good USB dac, like from Scott Nixon, and it will sound better than any CD player in the price range of the DAC ($500).
Or to simplify things even further (budget), check out the new 2 channel Outlaw receiver that received a very good review in Stereophile earlier this year, it has a USB input... powerbook straight in (it would not sound as good as a dedicated USB DAC though). But I think you should look at amplification first, be sure to check out integrated amps from Creek, Rega, Roksan, to name a few in addition to your list.
Good luck!
Or to simplify things even further (budget), check out the new 2 channel Outlaw receiver that received a very good review in Stereophile earlier this year, it has a USB input... powerbook straight in (it would not sound as good as a dedicated USB DAC though). But I think you should look at amplification first, be sure to check out integrated amps from Creek, Rega, Roksan, to name a few in addition to your list.
Good luck!