Well I wasn't really good with my old system, I wasn't able to build a new pc due to the cost. I'm doing a lot better now though and can afford what I want but as I said I don't really care about gaming over 1080p. I was pleasantly surprised by how much of a difference the new cpus make in some games even on a 750 ti but it is still holding me back. I am tired of waiting for things to be honest lol.OP, if up until now you were good with your 7 yr old system and a 750ti, then I suspect a 970 or r9 290 will last you a couple of years. If you have the money, then get what you want and enjoy, otherwise look at the price-performance and your personal tendencies over the long run to determine what to put in your system.
Since you upgrade infrequently, you could certainly wait and see what AMD's new parts do to the market. You do not seem to be in a hurry.