Try these. I use them all the time, for everything from MFUs, to receivers to viper boards. You can cut them with scissors, they stick like crazy but still pull right up with slow, steady pressure, and when they get dusty and lose the sticky you can run them under warm water and bring them back to life as good as new.

http://www.amazon.com/3M-Mounting-Sq.../dp/B00004Z4A7

I also use a lot of Velcro for stuff like speakers, LVAs, and even smoke units.

The Scotch foam squares are also very useful.