Anyone who is unconvinced that religious communities should find ways to recognize same-sex unions ought to read this article by Andrew Sullivan.
Sullivan takes terminology very seriously, and he is correct to do so. I don't think it's possible, at this stage, for halakhic communities to accord gay unions the same status as heterosexual marriages. Once we've grown accustomed to sanctifying same-sex relationships and "alternative families" -- that is, once the "custom of Israel" has changed somewhat -- we may be able to revisit these issues and come to different conclusions. But, one thing at a time.