It depends on the character, really. I've had some over the whole spectrum, of those that were not clerics, paladins or druids. Many of my fighter characters tend to be religious. Rogues could go either way; one might be like the tomb raider in The Mummy , with all the various amulets and charms of every religion, while another might disdain anything he could not sell.
I've had characters make conversions, too, from one to the other. One thief I had was saved by an impromptu divine intervention. He took a level of cleric, and was a devoted follower after that.