I will never buy a desktop again, because even in times like these when a pre-built system is often cheaper than I what can build myself, bottom-end computers are useless and always have been.
If you ask me, the place where pre-built computers always fail is in graphics. "Integrated" graphics, whether they're integrated on the motherboard or on the CPU die, are for shit and will continue to be so for years (and yes, that does include Sandy Bridge). Current integrated graphics cannot reliably show video at 720p, which is now the lower end of high-definition video.
If you have a fast internet connection, the problem is even worse, because many services (ahem, Netflix), stream video according to the available bandwidth, not the actual capability of the system. The result is a hitching, pausing, unwatchable slide-show. This is the main reason why nobody video-conferences, by the way, even though that tech has been available for fifteen years. It's because someone in the mix always has a Dell that won't do it.
System-makers simply don't give a shit that your "HD-capable" system is only "capable" if you add a discrete graphics card that costs an extra $150 (to $1000). They know the vast majority of their customers have no idea what I'm talking about, and expect them to trash their wheezy bottom-feeders in a year or two for something more expensive, adding the cost of both to the user.
Note for example that many box-sellers will offer an "upgraded experience" version that boasts "up to 3X better graphics performance" from the base model. (See e.g. the Dell Inspiron series.) That's with the very cheapest, shittiest discrete graphics option available, and you're expected to pay a premium for that horrible option.
I recommend simply tacking $150 to any low-end pre-built system you look at, and make sure that at the very least it has a PCI slot for a drop-in graphics replacement. You're better off buying the card separately and doing it yourself, because the card your manufacturer will offer will--again--be the worst possible option for you, because it's cheap to them.
Or, if you want someone to build a much, much more capable computer that may be worth having five years from now (instead of five years ago, which is where the bottom-feeders are now), the Tech Report has been offering reliable system building guides that rarely disappoint.
http://techreport.com/articles.x/22513
"The Econobox" sounds like it's right up your alley, about $700 if you already have the monitor, keyboard, and so on. It is their lowest-end suggestion, and even though it has a slower CPU it will still blow a comparably priced Dell Inspiron out of the water because the Inspiron relies on terrible graphics, while The Econobox wisely aims for the best it can afford within its price range.
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