I'm not sure what the difference is between "Firefox Nightly" and regular old Firefox. Basically, "Firefox" is the stable release. It's the one most people use

I'm not sure what the difference is between "Firefox Nightly" and regular old Firefox. Basically, "Firefox" is the stable release. It's the one most people use, and should use. It's currently at version 17, for people who actually still care about version numbers :) On top of that there are three release channels that offer preview builds of varying levels: * Beta -- is exactly what it sounds like. Beta builds of what will become the next release of Firefox. Beta builds currently are version numbered 18. * Aurora -- stable but pre-beta. Is two "versions" ahead of mainline Firefox, so Aurora builds are currently version numbered 19. * Nightly -- the bleeding edge. Rebuilt every single night from latest code, these are three "versions" ahead of mainline, so currently carry version number 20.