One of Church Logo Gallery's 7 Rules For A Great Church Logo is Authenticity. Your logo has to have the same personality, and tell the same story that people will experience when they step into your church. If you promote yourself as one thing, and the experience isn't consistent with the expectation, the visitor will be disappointed. In all likelihood they won't come back.
A recent Los Angeles Times profile on Pacific Sunwear (retail clothing store) CEO Gary Schoenfeld illustrates this in a business setting. Schoenfeld said after being offered the PacSun job, "I went out and looked at some of the stores, "Schoenfeld said. "I called back and said, 'No thank you.' I didn't like what I saw." He said he was put off by the cluttered stores, excessive discounting and the lack of authentic surf and sport brands."
Schoenfeld eventually took the job, but the point was that his experience wasn't what he expected, and PacSun's claim to be a surf and skate clothing brand created a disconnect when their he discovered they didn't carry authentic brands. He was turned off enough that he initially turned down the job.
What about your church? Is the image your logo (and all your church communications) consistent with the experience people have when they visit your church? Your logo plays an important part of communicating who you are, and can influence expectations. Make sure your image is saying the right thing.
Link to L.A. Times article: http://www.latimes.com/business/la-fi-0206-himi-schoenfeld-20110206,0,4328801.story