My favorite episode is probably road to rhode island, when stewie and brian are in the motel and stewie wakes up and touches the hot radiator and says "Damnit to puss spewing blood gutted hell!"
Next he goes to pick up the phone and says "what's lois' nimber? 867-5309, no... Damn you Tommy Tutone!!! 111-1111, no. 111-1112, no."
Definitely my favorite scene.