ko888 :
The Radeon R9 280 is just a rebadged Radeon HD 7950.
The Radeon R9 285 is now the replacement for the Radeon R9 280.
Uhm, no. The 285 is just an oddball. The 285 only has 2GB of memory and the 280/280x have 3GB, big difference.
I am a budget minded individual so I would opt for the 280x. It has enough memory and performance to play all the games and will not set you back as far.
In terms of performance the R9 290x and GTX 970 really trade blows and noticeable difference between the two is very minimal, both great cards. If I had to pick one or the other new though; thanks to its efficiency, low operating temperature/cost, and overclocking headroom I would chose the GTX 970. If I were buying used, I would get the R9 290x because they can be found for quite a good deal on ebay if you wait one out.