An adaptor that lets you game or stream with Ethernet-like ping, even when your room doesn't have an Ethernet connection.

External Sound Card so that I could boost the energy to my Surround-Sound speakers from my PC. An added benefit is that it moves the sound controls from software (my operating system (Windows 7)) to hardware (a physical dial), which is so nice to have if you like tactile feedback and don't like fidgeting with screen controls. [Creative Store Link] (it's usually cheaper on resellers like Amazon)

If you're unfamiliar with what a VPN does, Nord's "What is a VPN?" page will explain the main features. I like it because it's so easy to use on Windows, Mac, and Linux (!). They also offer apps for Android and iOS and light-weight browser extensions for Firefox and Chrome. 5000+ servers in 62 countries and Netflix doesn't block you when you use it. Please consider using my sign up link to support a month of my own subscription :)

I recommend qBittorrent if you're going to do any peer-to-peer downloading. It is free, open source, and has no ads. I especially like that you can see what peers you're connected to when you're downloading. It also has magnet-link support. Download it from their website (choose the "stable" version).

Robust little WiFi access point that I use to extend WiFi to the back of my house, using the PowerLine adaptor as the input. Having the two WiFi frequencies also allows the signal to travel further (2.4 GHz supported by both new and old devices), as well as supports a higher bandwidth for newer devices that doesn't travel as far (5 GHz). Also has 4 Ethernet ports. [Amazon UK Link]

Solid State Drive that I can't recommend enough. I replaced the failing Hard Disk Drive in my 4-year-old laptop and it was as if I bought a new computer. I also use one as the main drive in my PC. [Amazon UK Link]