I'm an atheist and I like christmas. I get what you mean though, the religious part of it annoys me, but it is overwhelmed by the "jolly" commercial part of it.
I'd like to expand on this subject a little though. In Holland pretty much all holidays are grounded in Christianity. As an aspiring multi-cultural country I find this highly irritating. It would be wiser to have holidays that have nothing to do with any religion, but everytime this is suggested Christians bring the "tradition"-excuse.
If it were up to me, religion had no say whatsoever in the public domain. That doesn't mean we can't all have a good time though