SSDs are nice, but rather pricey. A very good option, however, if your projects are smaller and you don't require a large drive. Most of my projects are a few hundred gigabytes tho, so I stick to standard spinning drives.
What I've done at home (I'm a professional editor by day) is get a USB3 RAID1 enclosure (here, on amazon) with 2 of these 7200RPM 3TB drives. It's plenty fast with USB3 to edit R3D files through Premiere, plus it clones the main drive for redundancy in the case that your primary drive fails. I routinely connect it to both an iMac and MacBook Pro and it works flawlessly with the USB3 on each.
I have the following hardware setup
The whole setup is less than 1 year old. Additionally, any video files that are older than September play perfectly.
Back-up at the end of each month. Trouble organizing? Consider this for naming project folder: YYYY-MM-DD_ABR_Project Name - Addt'l Info
ABR stands for Abbreviation. I have stuff like "FRN" for friends' projects, "WRK" for client work, etc. You can also use a 3-letter abbreviation or so for different clients so it's easier to search through and organize. I use Bulk Rename Utility on Windows to copy the base folder name to add it as a prefix to all the footage clips. This way, I don't have multiple projects with 00000.mp4, for example.