I think the social aspects of belonging to an organization are important. There are many people who, as part of their individual churches, find a meaning which is suitable for them.
Secondly, I think that for some people the comfort that they find from their particular brand of Christianity is very important to them.
I also find that it can be very refreshing to meet Christians who are not dogmatic, who do not try to push their brand of Christianity down your throat, who are caring and pleasant human beings and who have found expression for their particular slant of Christianity within their particular church.
I also think that many of the older church buildings in particular are quite awe inspiring and fascinating, and are part of my cultural heritage.
Sorry, Can't agree about Richard Coles though.