CyberpowerPC Gamer Xtreme 1077 Intel Core i5 760(2.80GHz) 4GB DDR3 1TB ATI Radeon HD 5450 Windows 7 Home Premium 64-bit at NewEgg for 769.99.
Just to compare what you can probably afford to buy on your budget.
As for what I personally do. Set a budget and then save 3x that amount. By the time you have your total savings new and better hardware will be available.
And if, for some reason you really want to go all out check out Falcon-nw.com
ALSO: Read through this
System Buyers' Guide: $700 to $1700