Kim Wilkins writes about parents in fiction on her blog, Hexebart.
I agree with her final assessment - if I was fighting evil spirits I definitely would want my Mum along with me. In fact, I suspect I could leave it all to her while I stayed home and maybe put the coffee pot on. (Actually, Mum, isn't that what you are doing at the moment anyway?).
On the other hand, I sometimes fear that for the Noodle I have much too much in common with the Other Mother from Coraline.
The best parents in children's fiction, in my opinion, are the ones in the Swallows and Amazons books. They don't require any outlandish plotting or melancholy accidents, they just let the kids do whatever they please the whole time. And not because they don't care (unlike, say, the parents in many Diana Wynne Jones books); the mother wrestles with her desire to keep tabs on the kids and the kids are muzzily aware of it from time to time. The other device I enjoy for getting rid of adult supervision is from E.Nesbit - any of the magic employed makes the adults around just not care what happens to the children, no matter how long they disappear for or what weird events occur. Not even when the Lamb grows up from a chubby, happy baby into an alarmingly trend-conscious young gentleman.
Frankly I think this last device would come in handy from time to time in real life. Just a little dose of it.
The ones I don't like so much are where the parents are vampires. Enough with the vampires already.