Shapely 1.2.4 has been tagged (see http://github.com/sgillies/shapely/downloads). Sdists are available from http://gispython.org/dist and http://pypi.python.org/pypi/Shapely/1.2.4. This releases fixes bugs involved with loading the libgeos_c DLL/SO and generally improves the user experience in the case of not being able to load them, if you can believe that. If you try to import from Shapely without GEOS on your system, you get:
Also in 1.2.4, AttributeError is raised when you call a GEOS-backed method that isn't supported by your OS's geos_c version. In 1.2.3, you'd see IndexError if you called either of the linear interpolations methods with GEOS < 3.1. Exceptions are part of the API, too, and these changes make the API a bit more user-friendly.