Soon you may be able to execute Gnome/Gtk+ based programs NATIVELLY NATIVELY on Quartz without the X11 Emulation. Someone (thanks to exist) is working on the porting.

It may be the incipit of a new era for Open Source software on MacOSX. Take a look at this.

One of the most interesting characteristics of Gnome-oriented applications is the coherence between the HIG (Human Interface Guidelines) of Gnome and MacOSX.

Source: Melablog.it and StyleMac.com.