Something not performing as well as you would like? Its important to know why you want to upgrade, if there isnt a reason other than just wanting to upgrade i would wait for a little while longer until you need to, you get more for your money that way.
It would depend on what you want to achieve. You already have a great CPU and unless you do computational intensive work, there is no point in going X6. You could always get a newer/better GPU if some games start to lag. You could also get an SSD for your OS drive or even programs/games depending on your budget (but just as an OS drive, it would make your PC feel more responsive and boot faster).