Choose a motherboard for our computer
So its choice is crucial for your computer.
To put our Athlon II, we need a socket AM3. It also allows to use DD3 memory, which is the same price as the DDR2, so enjoy it. Therefore this is a first filter for use in stores.
There are several sizes including: ATX, micro-ATX and mini-ITX. Our choice is micro-ATX, but it's just to save a few centimetres on the box. In ATX, the choice and price offer is larger.
In contrary, in micro-ATX, there are only a few products Asus, DFI, Gigabyte and MSI. All good brands.
These micro-ATX motherboards all include a chipset that handles sound and video. For our office use this is perfect and we will save some money.
Maybe one day you will add a graphics card for video games, but the sound card will likely remain the same for very long. So let's choose the best chipset: Realtek ALC889A, it manages the 7.1 and a unique function for the integrated sound: it can re-encode the audio in DTS to connect any home-theater system by optic cable Toslink.
Two main choices are available, a Gigabyte with the poetic name GA-MA785GMT-UD2H and MSI 785GM-E65.
(Note: The manual of the MSI does not mention this downmix to DTS optical output, but the Realtek drivers provided are the same. It would be surprising to doesn't have it, but I can not guarantee anything.)
Gigabyte's advantage: 3 fan connector against 2.
MSI's advantage: 128MB of video memory (called "SidePort") against 0.
My choice is the MSI 785GM-E65, near $90. We will manage to pull a 3rd fan with other cables, but we can't add the missing video memory!