If you ripped them as Apple Lossless the first time around, copy them to the new machine and either stick with iTunes, or try Plex or any number of free players. A 500GB library will however be a fair few albums and iTunes wont be great to use at that size. Replacing the drive with an SSD will make a huge difference in that respect though.
SBT/Chromecast/TEAC T1 into TEAC D-T1 DAC or olde-worlde Rega Planar 2 controlled by Rotel RC850 into HH S500D or DACT Passive Pre into Mullard 5-20 monos. Then into Tannoy Cheviots and a Wharfdale sub. All connected by colourful cables.