Artwork said:
Thinking about this now. (+PSU~)
So.. @ James. I'm also looking at the r9 280x. I'm more for Nvidia as well, but the r9 series gets quite a lot of good reviews.

I looked at R9 280X because of budget constraints. If I could have afforded a 290X(like the superb Tri-X version from Sapphire), I would.
Just remember that while 290 and above is overkill if you don't want to go above 1080p, this overkill status is gonna be gone in 6 months at best. I'd tell you to find a 290X where cryptocurrency craze hasn;t picked up yet and get that instead so that you can play most games at max detail for a few months more, but if you are aware of what 280X can and can't do, the choice is yours.
Of course, you can also just wait until NVIDIA releases more cards in its latest Maxwell lineup. Even if you don't want to consider buying from them, there's some chance that prices from AMD will drop as NVIDIA releases more of them.