Is Islam a serious threat in Europe?

Muslim immigration and the much higher birth rate amongst muslims, extremist muslims like Amjem Choudary spreading hate, censorship of free speech (trial of Geert Wilders etc), threats of violence against those who criticize islam (murder of Theo Van Gogh, threats to Danish mohammed cartoonist and British author Salman Rushdie) - is Islam a serious problem? Will it get better or worse? Is there any chance Europe could eventually be a majority in Europe?