The celebrations in the wake of Mubarak's resignation are well deserved. The Egyptian people rose up and forced the resignation of a dictator of 30 years, who clearly did not want to go. It remains to be seen, however, whether Mubarak's departure heralds a new era of freedom (including religious freedom) and greater economic opportunity for all Egyptians. Many outcomes remain possible, as reflected in the fact that Hamas in Gaza and the Iranian government are both celebrating today's events in Egypt every bit as much as the US and Europe.
UPDATE: The only thing I've read today that makes me anxious about the outcome of the revolution in Egypt is the following quote, which headlines an article in The Guardian (here): "Nobody will be able to to exploit the system here ever again." Whoever said that must have a political system in mind with which I am unfamiliar.