Check out the following thread: http://forums.anandtech.com/showthread.php?t=2192841
It's a thread about mid-range (~$1,000) builds based on current prices that mfenn updates once a week.
If you do decide to build, I would suggest making a thread in General Hardware, where hard working fellow members will do what they can to get you the most for your money.
^This is what I would do if I were stepping into pc gaming and know what I know. A good mid range pc is a great way to start or get back into pc gaming.