> Assuming ~650MB per CD, and the 150 CD's quoted, and ~50% reduction using FLAC, I get just shy of 50GB total storage requirements -- compared to the 63GB 'apple lossless' quoted. (Again, why the appeal of proprietary formats for long term storage and future re-encoding?)

I did a comparison between FLAC and ALAC (a.k.a. Apple Lossless) on my CD library a few years ago (plus a few 48kHz tracks taken from DVDs), and the difference in total filesize was less than 10% so I doubt that is a major factor. I personally went for ALAC, as it has equal (EAC, VLC) or better support (OS X Finder, iTunes, Windows Explorer, Windows 10 media player, some tagging scripts, iOS) in stuff I currently use. Providing I keep a decoder with the files, its proprietary nature doesn't really bother me - I can always convert to xLAC if desired.