I dont know, Ive always found that no matter how long you wait and no matter how long you shop around the instant you buy something, something cheaper and better will come out. There is always something better coming right around the corner. I just say buy what you need when you need it. If your rig is cutting it now then there is no harm in waiting til the Haswell refresh or Haswell-E but if youre struggling to play even at medium settings then go ahead and pull the trigger.
Nowadays especially, whenever a new generation of something comes out, its not that big a leap over the previous stuff. I bought a GTX670 not very long before the GTX770 came out. At first I was pissed then I saw it was only 2-3% faster. Same with a 4770K vs a 3770K. What, maybe 5% faster?