Image via WikipediaLet's go ahead and complete this trilogy with some advice on Desktop machines. In the first post, I described the most important pieces to consider when searching for a new computer. In the middle post, I gave some advice on laptops in particular. Lastly, we'll take a quick look at some things to consider when purchasing a new desktop.
As I noted in the post on laptops, Apple makes it a bit easier to search for and find the best (although usually more expensive) price for their machines. If you are a teacher or students, you usually qualify for some minor savings ($50-100) if you buy through their education site or in store with an ID. The iMac all-in-ones are available and they generally run from $1200-2000 for the standard configurations. Another option would be to go with a Mac mini (usually sub-$700) and combine this with an existing monitor, keyboard, and printer. The mini does tend to be a bit less powered for the price, especially when compared to PC's. It's often a popular choice for a quick home media center setup.
Just writing the price point for the iMac scares me a bit, since the same or better configurations for PC machines can be found for sub-$1000 prices. All-in-one PC's found television exposure through HP ads, and other companies have followed suit with their own versions. You'll generally get the same specs as the iMac for a $200-300 savings, which you can pocket or use to upgrade processor, memory, or hard drive space. Of course, you won't get the iOS or the design strengths that Apple understandably allures its customers with (this writer included).
Where you can potentially save money is to purchase a desktop machine separately and combine it with an existing monitor, keyboard, and printer. As opposed to the Mac mini which is a bit underwhelming, PC desktops come in a much wider array of flavors and options, and they are no less underpowered than the PC all-in-ones. As always, keep an eye out for the big three (processor, memory, hard drive), and you will most likely find a solid machine for under $700. I'll close with a few site recommendations, which as opposed to the sample machines scattered throughout, will remain true over the course of time.
Sites for Research: