I used to, because I was brought up that way, and lived out my belief in a very concrete way by working for a time as a cross-cultural missionary. But I don't believe in God anymore, having at length reexamined the rationales I thought I had sufficiently examined while an undergraduate for either believing in God or not. (There is, of course, also the issue of WHAT to believe about God, as not all self-described believers in God believe in the same thing.) I have still have immense respect for persons who act out their beliefs at personal cost, but now I advise everyone in general to test their beliefs on all subjects against reality. Many of the online sources I read regularly to find interesting, thought-provoking articles for HN come from sites that have the point of view that people ought to spend more effort and care on examining their beliefs for truthfulness.