Computer hardware from PC and Mac, Raspberry Pi (with a little Cubie and BeagleBoneBlack tossed in) and even some Arduino tossed in. Everything from hardware recommendations to installation/operation/troubleshooting guides.
Software from both a development and application standpoint. Open Source recommendations and tutorials. Office suite applications, CAD software, Programming Editors and Development Environments and Music Production software.
One of the handiest computer accessories I ever purchased was a Favi Entertainment 2.4G wireless keyboard. It's far from being a decent everyday keyboard, but this thing just makes my life easier. Hard to find fault for what this does, when you get your hands on one. And it's got a red laser built in.