i have the same CPU overclocked to 3.3ghz with an ATI 5450 and for HD movies, music, internet and basic gaming it does great. those regor's just love to be OC'd.
the PS is probably overkill as you wont need anything near that amount of power. as for the ram, not to rehash the debate but if you plan on using the machine strictly to play movies and music, then 2gb will do fine. however, if you plan on running a an extender or two, using it as a home server, etc.. then you should opt for at least 4gb.