In the 80s, when your shiny new Beeb arrived, you'd run software off tape cassette -- or floppy disk if you were lucky enough to have a model with the disk interface and DFS ROM fitted. Nowadays, unless you're going for a fully authentic retro experience, neither of these options is particularly appealing. Ideally, you want something like a hard disk and a network connection.
IMHO the best options in 2017 are MMFS and UPURS. MMFS provides a hard disk / multi disk changer type interface via files on an SD card, and UPURS provides various connectivity options to an attached computer. Both connect via the Beeb's User Port.
Getting either of these running requires a bit of bootstrapping. They both run out of ROM, and I don't have any traditional EPROM chips or a programmer for them, so I'm modifying a Microchip SST39SF010A 128kB flash chip and soldering some extra wires onto the computer's main board to simulate multiple ROM chips.
This document is getting kinda long, so I'm breaking it up into multiple sections; follow the links below: