I have been a little board, and have been giving some of my friends a cheat sheet on what they should buy for their Dreamcast to get the full experience. Attached is a 2 page document that shows some useful items. The obvious ones are the Raspberry Pi to get online, but there are also some useful items. One such item is the "Smart Power Strip" that turns on the HDMI converter and DreamPi, when the system powers on. When the system is turned off, so do the other devices.
Let me know what else I can add, to make this more robust.