This is a common question - should I upgrade now, or wait a little later for newer hardware? I normally tell people, there will always be a newer, better CPU and GPU coming out every year, so do not wait, get what you want when you need it at the best value.

However, to add some perspective to your question:

1. CPU I think is not worth it to wait for the next gen like Broadwell.  If you see the past few Intel CPU generations - Ivy Bridge, and Haswell, there is really not that much improvement of performance per dollar, it is more like power efficiency which is good for mobile devices like notebooks, but not much impact to desktop.

2. Nvidia's next gen GPU (Maxwell) seems to also focus on power efficiency instead of outright performance.  The GTX750 / GTX750Ti is actually Nvidia's next gen Maxwell available today for desktops.  Even the latest generation of GPUs for performance seems to be recycled designs with minor tweaks, both Nvidia and AMD seem to be doing this.

As we progress forward, I think the focus will be on energy efficiency, meaning higher performance in a lower power envelope, rather than outright performance.  That is actually not a bad thing, today's CPU and GPU is more than enough to game at "normal" resolution of 1920x1080.  There is the law of diminishing returns here when it comes to absolute performance.