It's definitely not as simple as 'new consoles are using more cores' when you look at what they're actually using them for. Xbox One is talking about having multiple operating systems running simultaneously so you can switch between them instantly - that's not going to happen without reserving significant resources.
My opinion is this: performance numbers are not going to jump overnight. Multi-core optimization is not going to magically make a 4770k worthless and an FX8320 the new king of the hill. PS4 and Xbox One are scheduled for release in a few months, but how long is it going to be before devs are truly taking advantage of the systems power?
By the time you're seeing ports optimized significantly enough for the consoles multi-core architecture, there's going to be a whole new generation of Intel/AMD processors to argue over.
If I were buying right now, I'd buy for the performance I know I'd get at my price range, rather than gamble on what I may or may not get in the future.