Are there parts of the bible that should be taken metaphorically, figuratively or allegorically?

The Christian community is divided as to how to interpret various parts of the bible. There are those that are hard-core literalist who believe in the seven-day creation event, literal Adam&Eve, the Noah Flood event, etc.

There are many of have adopted a non-literalist view of the bible in light of the recent scientific discoveries about the nature of reality. The more science challenges the accepted biblical orthodoxy, the more ground the non-literalist yield to rationalism. The vast majority of Anglican vicars in the UK, for example are of the later inclination.

But the big question is - How do we know which parts of the bible to take literally and which to take allegorically or metaphorically? Having decided which to take non-literally, what non-literal interpretation should we ascribe to them? Should these non-literal interpretation be consistent with scientific realism?