Thomas Ricks (author of Fiasco and The Gamble) links to a fascinating discussion on his blog. Major General Mike Oates opened up a discussion on the blog for his Task Force Mountain regarding "Don't ask, don't tell." This sort of dialogue should be sought regarding a policy that seems anachronistic to civilians. It is good to see some discussion among those whom changes to this policy would affect.
Personally, I think the best argument for allowing gays to serve openly is that the same arguments were made about women and minorities. If racism and sexism in the military can be overcome... why not homophobia? Anyway, I'll let the blog speak for itself, now that I'm done bloviating.