The accuracy of the fundamental properties of the energy landscape of silicon systems obtained from density functional theory with various exchange-correlation functionals, a tight binding scheme, and force fields is studied. Depending on the application, quantum Monte Carlo or density functional theory results serve as quasiexact reference values. In addition to the well-known accuracy of density functional methods for geometric ground states and metastable configurations we find that density functional methods give a similar accuracy for transition states and thus a good overall description of the energy landscape of the silicon systems. On the other hand, force fields give a very poor description of the landscape that are in most cases too rough and contain many spurious local minima and saddle points or ones that have the wrong height. © 2010 The American Physical Society.