People are often surprised when they find out about my primary machine. Isn't it too slow? Celeron, yech! For some reason, everyone wants me to buy another computer, soon.
What I don't tell people is that it is also my girlfriend's primary machine. We usually work on it simultaneously, she running reasonably sized R jobs, while I grind some matrices from grids. And when I say simultaneously, I mean we are both logged in with separate displays and keyboard/mice, and are interacting with the machine at the same time. Often, at the same time, my computer is engaging in some fairly largish downloads, perhaps uploads, posting webcam pictures, running my webserver, periodically fetching mail and chewing spam. It is entirely normal to have the computer stay switched on for a week or so at a time, with some program running through the night as well. 7Gb uploads are normal. Writing 100+ data DVDs is normal. You get my drift.
I bought this machine last year at a measly price, and have spent nothing more to maintain it. My overall estimate of the price of this setup is $400. This sum is a one-time cost.
Think about that again. From the time I setup this computer, I have spent only $400 on it. (Not including the cost of the 200 or so DVD-Rs that I have gone through.) I bought this machine used, and the price I paid isn't unreasonably low: many such computers are available at around $200-300.
For these reasons, the new computer market is very unattractive to me. For a fraction of the price, I get a very capable machine which I can use as my primary machine. I get a great deal, don't pay for OEM software I don't use (hint, hint) and save a machine going to a landfill. There are great deals on both desktops and laptops, and for Linux users, it is a buyer's market. People are just itching to dump their hardware because it stops serving them. If I need another machine, that's where I'm looking.