Motherboards

What they do
They are the core of the pc.
 
Quality to consider before purchasing one
The motherboard is the real core of our pc. Buy a low quality motherboard and you'll have problems no end, including unexpected and mysterious crashes. Buy a low quality motherboard and you'll probably end up moaning later on when this does not recognise and accepts some new devices that you install. Buy a low quality motherboard, and you will multiply by 100 all your pc problems.

The important factors to consider (in descending order of importance) are the following:
1) Compatibility (no problems in the recognition of new devices)
2) Stability (no strange and sudden reboots or freezing)
3) Reliability over time
4) Speed
5) Possibility to overlock

What thing that is of fundamental importance is the Chipset. If possible, choose a motherboard with an Intel or VIA Chipset.

If you happen to see some low cost computers on magazines or in the shops, it is likely that they are providing a very low quality motherboard. Be aware of what you buy.

Also fundamental is to have a good RAM (always do the GoldMemory test, to ensure that there will not be compatibility problems. There are more and more RAMs which are incompatible with different motherboards so that the compatibility test is essential).

Obviously avoid motherboards which have graphic cards already integrated...
 
The average cost for a good quality motherboard is between 100 and 200 USD. If you decide to buy something cheaper, get as much information as possible ( you may regret not to in the future, in particular if you use the pc a lot).
Brands to keep in mind (Motherboards sale)

1) Abit (excellent although expensive)
2) Gigabyte (usually highly compatible)
3) Asus (the most sold ones in the world; sometimes may have problems with compatibility)

There are other good quality brands such as:
MSI Micro Star International, Tyan (very good, but difficult to find), Epox