I thought a good place to start would be to describe the various PCs used by PC Medic in the course of business and in the PC Medic household.
The oldest PC we currently use is a custom-built Intel 2.8GHz machine with 512 MB of RAM that is used mainly for back office duties. In addition, I use it for music production and, because of this, it's fitted with a fairly high-end Terratec sound card. This has a front-mounted break-out panel which allows great connectivity with the outside world, including midi devices. This PC is built around a Lian-Li aluminium case, which is my favourite case for custom builds - great access, true toolless assembly, terrific heat dissipation and not bad looking either. This machine is dual boot - Windows XP Home plus Red Hat Linux, though we rarely use the latter on this box.
The main workshop PC is another custom build, this time an Intel 3.2GHz chip overclocked to 3.5GHz, fitted with 1GB of RAM. Once again this machine sports a Lian Li case, this time in black anodised aluminium. This is a multi-boot machine kitted out with Windows Media Center Edition, Windows XP and Windows 98SE. If we need to bring Linux up on this machine we will use a live distribution, usually Knoppix.
Then we have the Shuttle box which was bought as a bare bones unit and fitted with a 3.0GHz Intel processor and 512MB RAM. This is located in our kitchen/dining room and is used as a home entertainment system. Our music collection is located on one of the two hard drives in this box and we stream the music to other PCs over the wireless network or to the Hi-Fi system in the living room via our wireless Squeezebox (more on that again). This PC is also fitted with a TV card for viewing and recording TV via DigiGuide's TV scheduling application that I'll explain more about at a later date. While it normally runs under XP it also has Mandrake Linux on it.
Upstairs in MHBD's office we have a Mac Mini running OSX, which is mainly used by MH for web browsing and e-mail as well as managing our photo collection, but also serves as a test machine for us to learn more about Macs. It's pretty, silent and OSX has a beautiful interface but is a little bit on the slow side, partly due to the fact that it employs a laptop hard disk.
Finally there's my trusty IBM X31 laptop running XP. This is about 3 years old now and, while its a very compact and portable PC, it's built like a tank. This we bring with us on customer calls where we need a working PC in place. There's a number of network diagnostic tools on it and I generally always bring it with me when working on or troubleshooting networks. This is the machine that we have Skype installed on as its portable and we can make our calls from anywhere around the house
All these PCs are running on a wireless network sharing a 2GB Eircom broadband service via a D-Link DSL modem and a Linksys wireless router - more on these again.