This back and forth arguing doesn't help the op. I own 3 rigs with the first having a 780 Classified and watercooled, the second 2 670FTWs in SLI and the third a Sapphire R9 290 Tri-X, The Tri-X replaced a Reference GTX680. I noticed an improvement overall in speed.
My 780 Classified is the fastest single card of the three (OC core 1306;mem1697) but it's powered by a 3930k @ 4.6Ghz while the R9 290 Tri-X is powered by a FX 8350 @ 4.6Ghz, In a benchmark such a 3D Firestorm the 780 pulls way ahead because of the Physics. That being said, the R9 290 is a great card that is super quiet and runs cool even maxed considering the history of the chip upon release. The Tri-X cooler is really impressive(and big).
Considering the ops, question, 770 vs 280X vs 290, from my personal experience I think his selection of the Sapphire R9 290 Tri-X is sound and wise.