Designing Kitchens and Bathrooms - Bath paint for ceilling a must?

I'm getting ready to paint my new bathroom with Behr paint (no complaints about that brand please, I've already heard them) and saw their 'bath' paint that had better moisture properties. It's a sateen lustre finish so it's a little glossier than I like.

Do you guys think it's an absolute must in the bathroom walls? How about on the ceilling?

I have no windows but hopefully my new oversized inline exhaust fan will eliminate most of the moisture problems.

The main difference between K&B paints and regular enamel is ther K&B has more mildewcide. I've painted many a bath rm with quality latex enamel with no problems - don't know how well you would fair with Behr. K&B is better than regular for kitchen and baths.