at the moment it is good, it will probably be able to run new games for a year or 2.
if you can spend a little more money, then get the gtx 770, which will be more future proof and will also run games at higher settings.
Make sure your PSU supports your upgrade though, for the gtx 770 you need 2x 6pin pci-e slots and 42 amps on the 12volt rail.
hope that helps you