the r9-280 and the gtx 760 both can be had for less then 250... and both are superior to that r9-270x listed above.
depends on your preference both cards are pretty equal, though i suggest avoiding 2gb gpus going forward, especially with titanfall and watchdogs starting the trend toward needing more vram.
here are two good choices for you. take the card you like better.
this 760 comes with watchdogs and 4gb of vram... so it will make a great SLi card down the road.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127748
this r9-280 is a little cheaper, and just as strong as that 760...
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127789
how to pick between the two?
get the r9-280 if you like to overclock (these cards are fantastic overclockers), don't want watchdogs and like a little more $$ in your pocket at the end of the day.
get the 760 if you want watchdogs, don't want to overclock (its a little faster at stock) or want things like shadowplay or maybe in the future plan to get a 2nd card for more horsepower.