The Board
Choosing the main board or motherboard for your new computer is vital. There are different types of boards and the come in different sizes. There are some that come with HDMI output to plug in to your flat screen TV and some incredibly small motherboards that could fit in a shoe box. The board you pick will have to match up with your CPU. If you decide you want an Intel processor then you will have to go with a board designed for an Intel processor.
Board Size and Power
Motherboards come in a variety of sizes. There are the full ATX boards which offer the most expansion ports, the micro-ATX boards which still allow you expandability yet allow you to use a smaller case and the diminutive ITX which are close the size of a DVD movie case. For the most part, the micro-ATX boards are a popular choice. They offer expansion PCI-Express slots and can be used in most computer cases. There are some that come with built in optical audio outputs as well as an HDMI connector for your television. With a full ATX board you will need to move to a full tower case. The advantage with these boards is expandability. You could have 2 video cards, a high end audio card and perhaps to network cards. If you choose the ITX form factor you will find your self building a PC that can easily fit on top of your desk with out taking up much space. One major drawback to these small boards is that the cases they fit in can have issues dissipating heat. Power consumption is another factor. The ITX boards will utilize the least amount of energy. As for the micro-ATX and the ATX boards, power consumption will vary depending on the peripherals and cards installed.