What do you mainly use it for?i
Is there any specific software you absolutely have to be able to use?
Do you have a compelling reason to get a desktop over a laptop?
If the answers are: browsing the web, simple word processing/spreadsheets; no; and no*, then I would urge you to take a look at chromebooks. I'm a huge convert, but of course a lot depends on the quality of your internet connection (you can use them offline, but it's not a very pleasurable experience) and on how happy you are for Google to have access to your every move. They are very competent machines for not very much money at all - I don't know US prices, but it wouldn't surprise me to learn you could get two for your stated budget. Get as much ram as you can, though. I have two: a 2GB machine that was my first, and in a back-handed compliment to that one I got a 4GB model. The older one is still eminently usable - it's the one I take to work - but the newer one is that little bit more capable.
I'm speaking as a confirmed linux fanboy, who cringes every time I have to use my wife's windows set-up :fckpc: - to be fair, so does she
. But it's telling that, while I have both my chromebooks set up to use linux apps, I spend the vast majority of my time using chrome OS. Now that I'm no longer translating for a living, I hardly use linux at all.
* I was forgetting that there are also chromeboxes, that allow you the classic desktop set-up (but they're much, much smaller than your classic tower case PC).
This one apparently comes in at US$200, plus shipping.