I remember back in the day when you had to manually set each component so they can all work together properly. All those damned jumper settings and BIOS settings, those were the days. Now, you just plug the color coded wires into the right sockets, plug in the cards, hell even the CPU is plug and play nowadays, turn it on, and put in the Windows XP or BeOS(for computer illiterates); Linux or FreeBSD for us Professionals.

Even if you don't feel up to par, ask a friend or something, 9 times out of 10 you can find someone who will tell you EXACTLY what you need for the computer, and build it for you for free, or a small fee like around 10 bucks, that's my fee anyways. Plus you can get tech support, as long as you don't badger them, that will come to your house for crying out loud. Now that is service!!!
ON EDIT: This obviously excludes laptops, unless you know someone who knows electronics VERY well.