What is a good first time gaming computer for around $800 or $900?

Focus on the most important options- a quad core processor at 3.0 to 3.4GHz. 4GHz ram, more than that is wasted, people are overkilling on ram nowdays because it is cheap but my gaming desktop uses 37% of the 4 gigs most of the time. A good video card like any of the $150 to $200 cards at Newegg.com [I always use Newegg to compare prices as it's my favorite store.] Cost=speed in video cards. Get Windows7, a good processor cooling fan for $40. 500GB hard drive is plenty big. All other parts are similar and don't make any gaming difference.