Ask HN: What does your self hosted stack look like?

I'm curious to hear what others have found useful. Whether it's your OS, the services you are hosting, or even general tips on things like buying hardware on a budget or how you implemented a cheap/free DDNS, I (and probably the rest of HN) would love to see what's popular among self hosters.

(Disclaimer: I am in the process of setting up a self hosted server, so your answers may help me with my setup.)