VoxBox Alert: This One's for the Dudes!
3M Scotch Heavy Duty Mounting Tape 1"x3.47-yd.
Great stuff! I have used this behind several pictures on my walls to keep them straight and have used it to fix other items in the house that have needed a little help staying on the wall. As long as the item isn't really heavy it holds up.
Nothing works like this mounting tape. I have everything in my house hung with this stuff.