ARS Technica has published a new HTPC Guide, you can check it out over here if you have plans to build a new HTPC system.
The home theater PC (HTPC) market is very different than it used to be. Two years ago, the market was more or less DVRs and the HTPC, a few tentative OEM takes at the market, and a few standalone boxes.
Today, the HTPC space is much more crowded, and the market for these devices is not nearly as clear.
In some ways, building an HTPC has never been easier. Buying one, even, is a much easier task, with fairly workable pre-builts such as the Dell Inspiron Zino HD and Acer Revo nettop. The trickiest part of getting encrypted cable/satellite feeds into the HTPC is just now becoming doable, and feeding streaming or already-downloaded content to your TV is often made easy by the fact that a lot of existing hardware (consoles, Blu-ray players, and even TVs) can do it out of the box..