Well , first of all you will have to make up your mind with the brand name i.e. which brand you want to buy. Let me tell you in this way..
DELL, SONY, Toshiba, Samsung and Lenovo all these brands are good and will work for you easily upto 4-5 years and you knlwo after 4-5 years technology...
Well if you want to take some help on motherboard, i mean want to check motherboard product guide or buyers guide then you can refer Motherboard Buyers Guide in Nehru Place Market - Computer Hardware product guide , this gives good details about motherboards..