Pluralism

Pluralism is the view that all religions are either equally true, or more often, equally influenced by human development but all containing a core of divine revelation.

On this view, no one religion is more privileged than another or can lay a stronger claim to revelation or to the truth of its doctrines. Differences in religion may be due to historical and cultural influences that will inevitably differ from place to place through history, or to different divine revelations given to different people out of sensitivity to their different social/cultural contexts.

From a Christian perspective, a pluralist would be one who chooses to self-identify with one particular faith (Christianity) for whatever personal/cultural/aesthetical, etc. reasons, but does not believe that Christianity is "more true" or above other world religions and affirms the role of God in all religions.

A few pluralists from the Christian tradition include:

G.E. Lessing
John Hick

See also:
The Wikipedia entry on "Religious Pluralism"