Here are some of my boy bedrooms. This is RH's Atmosphere Blue. I had it color matched at SW. It really looks nice .

That is beautiful with the white trim and built ins.

Here's another post that shows several blues.

Laurie

Here is a link that might be useful: blues

Mine probably isn't as light as you were thinking, but here it is:
SW Dockside Blue

Have you tried BM Lake Placid? I did that in my son's room and liked it so much, I used it in my downstairs bathroom, too.

acountryfarm, what color is your white trim? It looks perfect with the blue!

We have BM Sterling in a teeny tiny powder room and it's a lovely, very pale gray-blue. Painted the trim White Dove and it's a nice contrast.

Thanks everyone for your posts and photos. I think we are going to go with either the Gray Wisp - I like the fact that it is a very light blue or Glass Slipper from ICI ( a friend used this in their house).

Thanks again!

BM Sea View; I wanted something not to bright that would go with denim, and it has just enough gray in it.