F1a...
That would depend on which format you rip the CD's to. Assuming FLAC, off the top of my head you'll need probably 90+ gigs of storage space. If ripping into WAV, 150+ is probably your minimum number. These are guesstimates, but probably good baselines to start with.
Personally, since SSD's are quite a bit more pricey, I'd have a smaller SSD for the server to use for playback to your DAC, while having a much larger HDD as an external drive to actually store the music.