Nvidia has a few more chips in its pocket. In addition to the soon-to-launch GTX 580 it also plans to release the 570 and 560 cards.
The GTX 570 will wait until Nvidia runs out of GTX 470 chips and cards and we are hearing that the GTX 560 might come this year. As I hear, it is a slightly improved GF104.
After a few months there should be a Geforce GT 540 and 520 cards for the entry level but they are almost certainly aiming for a 2011 launch.
Decisions on whether to launch some chips or not are changing almost on a daily basis, so the Geforce GTX 560 might also launch in 2011. It is up to Nvidia to figure out what to do with the GTX 460, which is doing quite well. Price drop perhaps?