Building a computer, trying to keep the price low, does motherboard matter that much?

that board has a lot of possibilities i would get AMD Black Edition - AMD Phenom II X4 3.4 GHz Processor that would make that board awesome and 4-8gb of DDR3 ram and AMD Radeon™ HD 6990 Graphics then get the tower you want and build it it would make a great gaming pc cant forget the power supply Ultra ChillTEC 939/AM2/AM3/775/1366 Thermal Electric Overclocking CPU Cooler With Controller