It was obvious from the jeers coming from Tahrir square during and after Mubarak’s speech that the protesters were not satisfied. The Muslim Brotherhood is now on record saying so. The WSJ reports:

The move wasn’t enough to placate protesters, however, who have consistently demanded that he step down immediately. Angry shouts rose from demonstrators massed in central Cairo’s Tahrir Square after the speech.
The Muslim Brotherhood, which is working with a coalition of opposition groups, was quick to say Mr. Mubarak’s pledge to step down months from now wasn’t enough and that the protests will continue.
“No one is satisfied,” said Mohammed Morsey, a spokesman for the group. “He and his system have already failed, and the people do not want him to continue with his colleagues. He has to leave.”