"Generally speaking, the errors in religion are dangerous; those in philosophy only ridiculous" - David Hume.
Obviously we have to consider who is saying this - David Hume is easily the most famous atheist. Being an Atheist he took a dull view of religion.
There is something to be said for this idea though. Countless wars and bloodshed has been spilt over religious differences - they still are, you can't really think of any philosophy which has caused the suffering. Although one must be careful not to allow a philosophy to become your religion. I'd argue, Marx had a philosophy and this philosophy has become a religion for many.
Taking this view, maybe this is the difference between philosophy and religion. Religion is dogmatic and doesn't allow room for real discussion, but a philosophy is simply a set of ideas, which are there to be discussed and exchanged. Each person can adhere to his individual philosophy without corrupting another's.
This is me just playing with an idea. What do you guys think?