Kwanzaa is arguably the 'Islamic' holiday of this time, although it isn't technically Islamic. From what I understand, it began in the Afro-american Muslim communities as a sort of Christmas surrogate for their children (kind of the same reason Hannukah was raised from a minor festival to a big deal). But it isn't Islamic in nature, per se, so you really can't call it such any more.
I think, actually, it was founded by a black secular humanist that wanted African-Americans to stop observing Christianity.
From the Wiki article:
In 1966 Karenga created Kwanzaa while living in California. There, he was the leader of the black nationalist US Organization and he claims that his goal was to give an alternative holiday to Christmas. He later stated, "...it was chosen to give a Black alternative to the existing holiday and give Blacks an opportunity to celebrate themselves and history, rather than simply imitate the religious practice of the dominant society."
But anyway, yeah, I don't get too upset over the "Happy Holidays" thing. It's not kicking Christmas out, it's simply being inclusive towards other festivals. Just as we wouldn't want non-Christians to walk all over us, we should be willing to show them the same respect.
Raising a fuss about "The War on Christmas" only makes us look bad. There's better hills for us to die on, politically speaking.