This is a list of my recommended or preferred solutions in the given categories. These are usually operating systems, protocols, or services. For my applications and online tools see my toolbox.

I have used and have had experience with a great many firewall and router OS's and have found pfSense to be hugely powerful and flexible, while still being relatively simple. And does it while being completely free and has a huge and active community. There is a company behind the OS that takes money for hardware and official support, but the free OS is in no way hampered like a lot of such systems.

I must admit that I have not a lot of experience with the boutique NAS systems. I have always had an extra Windows machine that served what centralized file serving I needed. FreeNAS had crossed my path a few times and when I finally decided I needed a real NAS with some flexibility it fit the bill. I looked really hard at it's competitors too. Even went back and forth between it and Nas4Free, which is an offshoot from it, but found FreeNAS checked my particular boxes much more thoroughly.