[STCrowley]

My mother (the craziest of Grammar-crazies) taught me that to say "more beautiful than me" was wrong. I still say it, but only when I'm being relaxed. Good English, my mother said, was "She is more beautiful than I." But the 'am' that Susan53 mentioned is 'understood.'

But, most native speakers will say "More beautiful than me." It's one of the mistakes that you're supposed to make. (Unless you're in a formal situation or trying to sound smart. Then good grammar can really help.)