A few refurb SanDisk Sansa Fuze or Clip players and an assortment of 2GB to 8GB uSD cards fills the need to enjoy FLAC based CD-quality music on-the-go. No, you don't need Rockbox (alternative firmware). Native vendor firmware plays 44KHz/16-bit/2-channel FLAC without issue. Labeling uSD cards is a little tricky, and for that task I'll cut an Avery 6737 label in half and write using an ultra-fine (0.5mm) tip pen. After a few insertion cycles of the storage card, the label settles enough that it does not bind on the socket. All of my music is stored and labeled this way and fits in an Altoids tin. Duplicity encrypted backups are stored offline on 1TB or 2TB rotational platter drives. The upfront cost of this setup is about equal or less than what I paid in the 1990's for a used portable CD player, NiCad batteries, and CD case storage.
What I would like to see (as a consumer) is the wider adoption of 96KHz/24-bit FLAC playback capability on portable devices. CD quality isn't good enough for me to justify paying more than the cost of a local live show for it. I can barely notice the difference between CD-quality and a higher resolution signal, but I -do- notice the difference. I.e most people do not notice when they crank up the volume of a player beyond the line input level of a stereo system, and I do know this, it is grating to my hearing and detrimental to enjoying music. Worst yet about our economy today of buying and selling music, most of this music is damaged by the compression methods to the point where not many people can tell the difference anymore. It all sounds like shit at playback no matter what you do to it.