NVIDIA's GeForce GTX 580 was a powerhouse of a card, it pushed the company away from the mess that was the GTX 480 with its various power, heat and noise-related issues, and showed the world that yes, the top dog could still be, top dog.
They reiterated this with the GEFORCE GTX 680 (with the capitilization meant to emphasise the word GEFORCE I'm guessing) and are now enjoying the fruits of their labor. The GTX 680 kicks ass, which means the GTX 580 can slide into retirement, put its slippers on and enjoy a nice, fat green pension for the rest of its life.
The GeForce GTX 580 officially launched all the way back in November 2010, and has enjoyed the crown of fastest single-GPU card until the day AMD launched their HD 7900 series. That didn't last long for AMD as NVIDIA launched the GTX 680, taking back that crown. Enjoy your retirement, GTX 580, my GTX 570's are enjoying their SLI goodness in my PC right now as I type this.