If you can afford the RX 480 then that is the one to buy. It is roughly on a par with a stock GTX 980.
However if this is not possible, assuming you have a 1080p 60Hz monitor (or less) then the R9 380X is a good choice.
I picked up a Sapphire Nitro R9 380X for 219€ not long after they launched for use with such a monitor and I've not been disappointed.
With 4GB vram it should last you a good while yet. With the exception of Doom 2016 and GTA V I can max out every game at 1080p and get 60 fps all the time/almost all the time at stock settings.
It overclocks well (for a Radeon card!) and for the price I paid, the only thing that can beat it 'bang for buck' is the likes of the new RX 470 and RX 480 it appears.