Walls and Ceilings - To Prime or not to Prime

I have recently finished a bedroom in the basement for my daughter and I am now to the point of painting/wallcoverings. We gave our daughter free reins to decorate as she wants and is going to do a burgundy paint on 3 walls, and wants to wallpaper one wall. I know to be sure and prime where she is going to paint, and I would assume I should prime the wall she plans on wallpapering. Is this a correct assumption?

I also assume that this wall will change 5 times in the next 5 years. Is there anything I can do now that will help me remove the wallpaper easier in the next few years?

My final question of the day. I have a knockdown ceiling in this room and it requires painting. Should the ceiling be primed before I use ceiling paint, or is there a ceiling paint that is an all in one type?

Thank you for your imput,
Mike

The wall should definetly be primed under the wallpaper. The better the wall is sealed the easier the wallpaper can be removed later.

Although it is better to prime a knockdown ceiling 1 coat of flat latex will cover sufficently.

Ditto Marksr's answer,

Although I am feeling witty tonight so I'll throw in...

If she is a teenage daughter, you might want to consider thumbtacking the wallpaper to the wall, as it comes off very easy, and filling thumbtack holes can even be done using toothpaste! (college trick). :)

I have actually used that good ole dorm room trick, saved me about 50 bucks in fines. I have done everything I can think of to talk her out of the wallpaper, unfortunately she thinks my mother-in-law is a decorating genius and the wallpaper is her suggestion. At least I talked her out of the fake brick wainscoat.....

Anyhow. Thank you for the advice.

Mike

The wall should definetly be primed under the wallpaper. The better the wall is sealed the easier the wallpaper can be removed later.

Although it is better to prime a knockdown ceiling 1 coat of flat latex will cover sufficently.

Really? I would think that if the knockdown was not primed to begin with, it should be primed first...? Also, I've never been able to get away with 1 coat, even with good (non-Behr) paint. I guess that what seperates the DIY'ers from the pros....!