There's a great post by Andrew Brown over at Caute about inhabiting paradox, which addresses the identity of British Unitarianism - is it Christian, post-Christian, pluralist, eclectic...?
I blogged about this in a series of posts last year: The empty path; Is Unitarianism Christian?; Roots hold me close, wings set me free; Golden heresies; Blessed are the poor.
I think it is very important to keep inhabiting the paradox. Places of tension are places of creativity.
I think that in rejecting the doctrine of the Trinity, as well as establishing the right to interpret the Bible for themselves, the Socinians did something else important. The doctrine of the Trinity, and Christ's divinity within that, could only be made known to humanity by a particular revelation (and therefore available only via Christianity); whereas the idea that the Divine is either one or many is accessible to reason and experience, and therefore available to all religions.
Andrew pinpoints correctly that there is a debate between "those who would like us to land definitively on the side of our inherited Christian tradition" and "those who would like us to land definitely on the side of open-ended change and to insist that we must let go of our distinctive traditions and roots and move into an undiffentiated pluralistic landscape".
I agree that we should not plump for one side or the other of this debate.
I think there is a third possibility: that we acknowledge that Unitarianism has always divagated between these possibilities, and that the Unitarianisms of the past contained the seeds of the humanist element, the earth spirit element, and the pluralist element. It is not (as I am sure Andrew is aware) that the Unitarianism of the past was uniformly Christian, and that the pluralism is a new thing. Rather, there were the Transcendentalists, deists, theists, pantheists, humanists and nature-lovers (Coleridge, Morganwg, Frank Lloyd Wright, etc). And Servetus was inspired by the religious pluralism of Moorish Spain and by reading Hermetic texts.
I think that it is possible to develop a distinct Unitarian tradition with its own particular traditions and rituals, and that this is what is happening with things like the flower communion, water communion, chalice lighting, and Unitarian ways of celebrating Pagan seasonal festivals, or doing bread and wine communion, or lectio divina, or other spiritual practices. And there are so many excellent Unitarian writers on spirituality and religion who have created a rich and deep culture for us to draw upon.