I feel my girlfriend's ex was 10 times better than me?

Title says it all. I feel my girlfriend's ex was infinitely better than I am, and that I'll never amount to what he was. He broke up with her, and then she met me a few months later and began to date me. It's just that looking through her myspace, facebook, etc, her old posts from when she was dating him are just filled to the brim with sweet stuff about him. She was truly in love with this guy and basically thought about him every waking minute. I absolutely HATE this guy because I feel I can never be to her what he was. What could I possibly do to feel needed by her and thought of by her all the time like she did with this guy? It drives me crazy thinking about it.