I haven't been a fan of the GTX 980, since the introduction of the 980 Ti. With that said, the one exception is 21:9 2560 x 1080 resolution. I think that lone resolution represents a sweet spot for the GTX 980 (not Ti). The best option for 1440p remains the GTX 980 Ti.
Recommendation: Purchase an EVGA refurbished b-stock GTX 980 Ti:
http://www.evga.com/Products/ProductList.aspx?type=8&family=GeForce+900+Series+Family&chipset=GTX+980+Ti
* That card represent an incredible value for $550. It's out of stock today but you can set a automated reminder when it's in stock. If you do that and you are prepared to buy it at a moments notice, you'll very likely be able to purchase it by this coming Friday
Option #2: Purchase the EVGA b-stock GTX 980:
http://www.evga.com/Products/ProductList.aspx?type=8&family=GeForce+900+Series+Family&chipset=GTX+980
* I like the $359 option better than the reference model's $399 price point. If you're intent on getting just the 980 (non Ti) then $359 is a reasonable amount to pay, but I wouldn't even consider buying a new one for $500.
These are my recommendations.