for a more direct list-like suggestion :-
ram : uses only 1.35 volts , less heat when using 4 modules , u should get 8gb .
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231326
mobo : p7p55d-e , great single gpu with 7 atx expansion lots , sata 6gb/sec , usb3.0
case : antec 300 steel black , 54$ shipped .
psu : corsair 550vx .
video card :-
for everything blue ray and light gaming : radeon 4670
for mid range gaming (your limit) : 5750 or a faster 5770 , your call depending on what games u really play if at all .
now , if u use photoshop professionally , get the xeon or 860 .
otherwise , get i5 750 at microcenter/newegg for 160/200 dollars . at has impressive performance .
an i7 920/x58 platform is really usefull for extreme overclocking and best performance with dual gpu's in sli/cf , but you dont need that AT ALL , so dont waste your money .
also , get 4gb ram first , you can always get another 4gb if you feel the need to do so after trying it out . installing more ram is easy and hassle free .
i would suggest $30 cooler master hyper 212+ , good enough for even 3.6-3.8 ghz with antec 300's sound airflow .