well I mean what's your budget? and correction on the price, R9 280x's are out of stock atm so they are more expensive than the GTX 770,
some GTX 770s are also out of stock atm but some pretty good deals are still up
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125463
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127742
Gigabyte Windforce and MSI Lightning, some of the more reputable models, up for cheaper than the R9 280x you found
Edit: and the R9 270x is a solid card, it's pretty powerful for it's price and would fit very well with the rest of your build
it's also got a pretty decent cooler, the Sapphire Dual-X's have always been highly reviewed, and furthermore, it's an oddball 4 GB version too, so if you enjoy multi monitor or high resolution gaming it's a decent card (though not as powerful as people would usually like for those types of situations)