TV tuner: An onboard TV tuner lets you watch over-the-air broadcasts on the AIO's display. If you subscribe to cable or satellite TV, however, you'll be much happier plugging a set-top box into the machine's HDMI input.
Avoid buying last year's models: Although you can score a big discount on an older model, buying an outdated AIO is problematic. It's unlikely to come with Windows 8 installed, and it probably won't have the type of multitouch display you'll want to use with Windows 8 should decide to update your OS later.
Remember that you can't upgrade: Upgrading a desktop PC is easy, particularly if you want to improve its graphics, storage, display, or optical drive. With few exceptions (such as the aforementioned Maingear Alpha), upgrading an all-in-one is at least as difficult as upgrading a laptop. The key is to buy as much computer as you can afford, so that you won't outgrow it too quickly.
Go big: You'll never regret buying a display that's too big--unless you lack the room to accommodate it. If you plan to put the AIO in a computer hutch, measure the space before you bring the computer home. But keep in mind what we said about 27-inch displays with 1920 by 1080 resolution.
Trust, but verify: As with any PC purchase, unpack and set up your all-in-one immediately. Make sure you have all its accessories, and that the entire system is working as it should.
Products we like
If you don't plan to upgrade to Windows 8, you won't care that Dell's XPS One lacks a multitouch display. The 27-inch, 2560-by-1440-pixel PLS display is so beautiful, you might not even care if you do upgrade. A beast lurks beneath that beauty, too, in the form of Intel's 3.1GHz Core i7-3770S desktop CPU and Nvidia's GeForce GT 640M mobile GPU. You also get a Blu-ray player, a 2TB desktop hard drive plus an SSD cache, and HDMI-in and -out. Dell is now shipping a version of this machine with Windows 8, but they're using the same non-touch display.
Lenovo turned heads this year with its IdeaCentre A720, which boasts an articulated hinge that allows its 27-inch display to lay completely flat--a great orientation for everything from sharing presentations to playing digital board games. The ability to angle the display so far back is essential when the machine is on a desktop, but you're using the touchscreen from a standing position.
And while Vizio is a rookie when it comes to building PCs, the company introduced a spectacular all-in-one PC in the form of its affordable CA27-A1. If you fall in love with this sleek, sexy machine, however, be aware that it doesn't include an optical drive. If you plan to stream music and video from a local server or NAS box or from the cloud, that won't matter a bit. Ditto if you buy all your software online and install it from the cloud. If you're the type who prefers to your software on disc, or who buys CDs and rips them, you'll curse that missing drive.