There is no difference performance wise between different models of motherboards. Its just that some motherboards have better overclocking capability and allow you to use more than one Graphics card. If you are not going to use more than one Graphics card. I would recommend a Gigabyte EP-35 DS3L. Its around $90 and overclocks beautifully.
Psu's are the hardest to shop for, because you have to know which brands are good and what to look for.
I would recommend either one of these two PSU's
Newegg.com - XCLIO GREATPOWER X14S4P4 600W ATX12V Power Supply 100-240V / 200-240V UL, CUL, TUV, CB, VDE, FIMKO, DEMKO, NEMKO, SEMKO - Power Supplies
Newegg.com - XCLIO GREATPOWER X14S4P3 500W ATX12V Power Supply 100 - 240V/ 200 - 240V UL, CUL, TUV, CB, VDE, FIMKO, DEMKO, NEMKO, SEMKO - Power Supplies
And if you want to learn about how to grade different type of psu's:
This is what I would recommend buying:
Motherboard: Gigabyte EP35-DS3L
Processor: Intel E7200 or Q6600 (whichever your budget allows)
Graphics Card: ATI HD4850 or HD4870
RAM: A-DATA, I have them and they work great.
PSU: Corsair 520HX or one of the XCLIO psu's I linked to.
Case: Whichever case you think looks the coolest, and is in your budget.