It's one of the few sections at AVS Forum that I recommend people visit.
YET: I also recommend people NEVER paint their wall for a screen.
Painting for a screen, or black out cloth, or one of the other solutions is great, but don't paint you WALL.
Walls are a part of your home, and are subject to shift with your home. I had a friend who spend 2 weeks making sure his wall was absolutely perfectly smooth with tons of sanding and spackle, and resanding. He carefully prepped, then painted the wall. Added some nice trim... then 6 months later, due to the environment of the 'home' and the normal wear of his home, a cracked appeared in the middle of the wall... his screen.
Instead, paint a material which can't crack and is already perfectly flat. Something which won't be structurally screwed right to your studs and won't be subject to the same stresses the rest of your house is going through.
