Certain Muslims have been on the rampage about a series of satirical cartoons published initially in a Danish newspaper, and then in a Norwegian one (see article here).
This is where the West needs to take a stand and say that, yes, we're a pluralistic people, but our very pluralism entails a deep respect for freedom of expression. Tolerance might not be the same as agreement or acceptance, but tolerance-- primarily marked by a forbearance from violence-- is crucial in a pluralistic society. Pluralism doesn't equate to spinelessness: it does indeed contain its own exclusivism, as I've written elsewhere. From the pluralist's point of view, some thoughts, beliefs, and behaviors are unjustifiable.
Religious satire happens, and it's no use screaming about it. From what I recall of living in Europe, Christ gets lampooned daily over there. Some of the most hilarious spoofs of Christianity I've ever seen come from the pen of French cartoonist Claude Serre, and he's not the only European to knock the Savior. That's one of the great things about the West: at our best, we don't take ourselves that seriously. Even the most sacred foundational figures in our culture are fair game. And thank God. I wouldn't have it any other way.
The idea that you cannot even depict Muhammad... sorry, but if Islam hopes to integrate with the West at all (and it's an open question as to how many Muslims seek such integration) that doctrine's going to have to go. Europe, in the meantime, will need to stop making excuses for Muslims who behave childishly in the face of mockery, and start remembering itself. I say that as someone with a deep love of Europe.
By the way... Muhammad has been depicted before. Here's one of the most famous renderings: the Prophet ascending on a mythical beast called a buraq.
(image snitched from here)