I have a 5 TB NAS (technically 4x2 TB of SSDs in RAID5, plus float space for backups of my servers), but it’s shared for music, video, books and audiobooks, and retro game ROMs, plus other necessities (personal documents and such).

I mostly enjoy older stuff, and don’t bother with 4k. I let the TV upscale it, don’t really care. Looks like I’ve got about 1.5 TB worth of video (movies, TV, and anime) at the moment, plus another 1.4 TB of music.