continued....
I built a PC a few months ago (I build one every couple of years) and finding the right motherboard to buy was a nightmare.
As I said, there are hundreds to choose from, and some of them are so similar it is almost impossible to make an informed decision without spending hours looking at each and every feature.
To narrow it down do as follows:
1) Decide a price. There are budget motherboards at say �30 to �50, then good midrange ones at �50 to �80, then top of the range at �100 plus.
So first decide how much you want to spend.
2) Decide if you want an Intel CPU or a AMD CPU. Motherboards can take one or the other so deciding which CPU cuts the number of motherboards available by half.
3) Choose a good "brand" such as Asus, Gigabyte and so on.
4) Decide on a size, like ATX, microATX etc
5) Decide if you want any special features like on board graphics or HDMI
Once you have made all those choices you will still have 50 or so to choose from so then it comes down to personal preference or what you can get at the best price.
I think chosing the right motherboard is the hardest decision when building a PC, once you have that most of the rest falls into place (except maybe the graphics card if you are in to gaming)