"Within that state, however, the name is relatively unimportant."
Not really. Within that state, gays will still be filing federal income tax separately, they won't be eligible for spousal social security benefits, they won't be permitted to sponsor partners for immigration purposes, etc... The GAO has recorded over 1000 federal benefits that do NOT apply to any partnership other than marriage.
Yes, just after I posted that, I realized that it was not only state benefits that matter, but federal ones as well. You are right: what the relationship is called does matter.
That said, I believe we should not budge on the issue of "gay marriages" or civil unions, whatever they are called. Once such arrangements are established, it would be too easy for a federal court to declare that civil unions are essentially the same as marriage and should be recognized as such.