From the Geany About page:
Geany is a small and lightweight Integrated Development Environment. It was developed to provide a small and fast IDE, which has only a few dependencies from other packages. Another goal was to be as independent as possible from a special Desktop Environment like KDE or GNOME - Geany only requires the GTK2 runtime libraries.
Anjuta, on the other hand, is a full-blown IDE used for developing GTK/GNOME applications. The following is from its About page:
Anjuta is a versatile Integrated Development Environment (IDE) for C and C++ on GNU/Linux. It has been written for GTK/GNOME and features a number of advanced programming facilities including project management, application wizards, an interactive debugger and a powerful source editor with source browsing and syntax highlighting.
Glade is integrated into the IDE and there is an option to build a subversion plugin.
Code::Blocks is an open source, cross-platform and free C/C++ IDE. It is built using the wxWidgets GUI library.