I guess this is Emacs' "primary" logo, which has remained pretty much unchanged since. But unless you leave the splash screen enabled, the far more familiar logo for most people is the one used for graphical shortcuts and thumnails. This one is derived from the horns of the GNU, forming a stylised 'E' in a circle. As it has been looking quite dated, over the past couple of months Nicolas Petton has been redesigning it [0]. Reception from the community has been mixed - there will always be people opposing any change - but overall, I think, quite favourable.

[0]: http://nicolas-petton.fr/blog/working-on-the-emacs-logo.html