You see... this really is about equality for all human beings.
Not too long ago, a white man couldn't marry a non-white woman (or vice-versa).
The judicial system had to step in and take a stand... they should have done the same today.
In my mind, there is no difference between civil rights based on race and civil rights based on sexual orientation.
To deny a person [consenting adult] the right to marry the one they love [another consenting adult] is unfair.
Legally speaking, there are no reasons for marriage to be defined as anything other than an agreement between two consenting adults.
Married couples have a "next-of-kin" status in the hospitals. They can file taxes jointly. They can receive Social Security payments when one spouse dies. They have bereavement time if their spouse dies. Same sex couples cannot have these same rights.
You can state a personal belief against it based on your faith, but [and this is something that makes America great and interesting] not everyone in this country shares your faith, that's why there's a separation of church affairs and state affairs.
Emotionally speaking, I am a believer in love.
And if you're lucky enough to be able to find a love, a companionship, that fulfills you and makes you stronger and happier... you should be able to live that love regardless of your sexuality.
Now, some additional thoughts from comments left "elsewhere":
I'm glad it was mentioned that marriage is a religious ceremony. I have a great idea, why not make all marriages legally equivalent to civil unions? That way it's not a one stop shop for a variety of rights.
As is stands now, when two people are legally married (because it's become a legal institution, not strictly a religious one) they will automatically inherit anything a spouse leaves behind upon death (unless there is a will that specifically states what goes where). Civil unions do not supply that.
... If a spouse gets laid up in the hospital and cannot make medical decisions for themselves, their spouse gets that right automatically. Civil unions also do not afford that same right.
... Sharing health insurance is not guaranteed to a couple bound by civil union.
... Social security payments for deceased spouses go to the living spouse, as a way to help provide for the one left behind. That's not so with civil unions. Etc.
Justice is, by definition, just. Fair, balanced and blind. Allowing a committed gay couple the same rights as a committed straight couple does not step on anyone's legal toes. What, in the daily life of a straight couple, would change if a gay couples marries? Nothing. Nothing at all. There are no biological reasons that homosexuals should not marry (because people will argue that marriage is regulated for good reasons... because you cannot marry a cousin).
And I do believe that the gay community HAS been fighting for some time for equality. Their fight is finally gaining a bit of ground, but their fight is not new. It's not happening overnight. What is so heartbreaking is that they finally had a victory in California and it was taken away from them by the "will of the people." Not because it was dangerous or unfair or anything like that. It was taken away because people feel (in their personal and usually religious views) that homosexuality is wrong... because a majority of people feel weird that two people of the same gender kiss and have sex and live a slightly different lifestyle. (I mean, who does the "woman work" and who does the "man jobs" in a homosexual household, right?)
So I'm allowed to be disappointed in the courts. They didn't defend the people that can't shout as loudly, they didn't stand up for their rights.
Also, I liked Kzinti's (humorous, but brilliant) idea:
"Marriage ought to be very straight forward, cut and dried. Like driver's licenses. If you had to stand in line like at the DMV, there'd be less divorce and if you had to renew your license every so many years, that would remove all these divorce cases from court. Don't like the situation? Let the license lapse. Everything is split as agreed to when you signed the license, like a prenuptial agreement.
Everything is decided fairly up front, including who gets the kids, what child support will be, if any, etc. Sign on the dotted line please..."