If your not overclocking, there is definately no purpose at all to use a peltier. Just use the retail fan that your supposed to. Using a peltier gives a lot of more risks that you do not need for a "non-overclocked" system. Peltiers causes exert a lot more overall heat, can cause severe condensation as well as require more power that your system may not have.
EDIT: As well as waste more money.