Your first priorty is your child. In my mind, holidays in modern day are simply a reminder to take time for special ocassions and celebrate them with family and friends. Decorations should include what you and your husband and kids like. For instance, I'm agnostic, but I've always loved angels...so I have about a thousand of them, LOL.
Why not approach your parents with this?: "When I was a child I respected your way of doing things, and now that I'm an adult I expect the same from you. I think it would benefit my children to celebrate the holidays, so that's what we're going to do. If I'm df'd and you decide to shun me, I want you to know that my kids and I are a package deal...you choose to ignore me, you choose to ignore your grandchildren." Then leave no room for argument. Just find a mantra to keep repeating...something like, "I respected your child rearing decisions, and I expect you to the same for me."
Of course it's beneficial for children to have a good relationship with their grandparents, but it's much more important for them to see that their parents are confident about their parenting. Trying to hide a normal life from yor parents may induce unneccesary guilt for your children and make you appear spineless and sneaky to them.
Maybe this will sound silly but I have pain now for the normal joys of childhood deprived of me. Yes I know I did not have the worst childhood on the planet and am not trying to overly pity myself. But it does pain me, rightly so. I have difficulty opening the door to trick-or-treaters b/c it makes me sad thinking of what I didn't experience. Same thing watching in-laws' kids open xmas presents, go to prom, etc.
(((((Rebel8)))). It never ceases to amaze me how people think that only those of us who were physically or sexually abused as children deserve any regret over how we were raised. Your saddness is very valid.
That being said, it's important for the OP to know that the only thing that helped me with the saddness I felt over my childhood, (jw related and otherwise), was giving my kids what I didn't have.