I mostly collect Blu-Rays. Though, I increasingly find myself buying 4K Blu-Rays. I buy DVDs when they’re the only option.
I store them in 5-tier Atlantic Mitsu racks. I currently have four of these racks. I use them because they’re cheap and flexible in terms of placement.
With movies and shows that I’m viewing for the first time, I’ll use the Blu-Ray player. Otherwise, I’ll pop them in my PC, run them through MakeMKV and Handbrake, and then copy the files over to my server. I have two WD Red 8TB hard drives in my server, though I’ve only just about filled up the first one.