The patron Saint and protector of Bucharest is Saint Demetrius the New, celebrated on October 27th, when tens of thousands of people from all parts of Romania and from abroad come to whisper a prayer next to his coffin. You can find his relics in the Patriarchal Cathedral in Bucharest (and you have to know that lots of people, especially from Orthodox countries, visit this church every Sunday).
By every standards, Romanians are very religious people. In Europe, they can only compare to the Polish and the Maltese, in terms of religiosity. The problem is that the level of religiosity does not mean automatically that the religious faith is equally strong - as duplicity is an issue in most maters concerning Romanians. But do not be surprised if you find out religion is very powerful in Romania.