when I was building out my NAS, the "sweet priced" drive was 750Gb. Now it seems like it is a 1.5Gb drive. I would be happy with Raid1 with 2 1.5Tb drives but at the time to achieve a large partition, 4X750Gb drives were what was needed. Of course, I'm still growing into the 2nd half of that terabyte ....
maybe if i figure out multi-channel high rez FLAC and keeping my fingers crossed for Sonos 3.0 :-)

Primary: 818v3+ID41, M6 stereo pair, M SpeakerLink cabling, Sonos+96kHz Cullen, silver DSW
HT: Marantz prepro, 271, DSP3300, 8K SE FL/FR pair, DSP M6x2, DSP320x4 (ceiling), black DSW, 520 RL/RR rear in-walls
Living Room: G65, 640 L/R in-walls, UHD722, MS600
Vac. Home: G61, HD621, 4xDSP3100, DSP3100HC
MDMS:NUC/ROCK+TrueNAS Core 12.0 ZFS file server