The only folder that I leave the ! on is the !Daz folder.  I rename all of the ones inside the main library character, pose, props etc folders.

I tend to organize some things by "theme" inside my runtimes, such as "shoes" and "jewellery" and "purses". Or inside my props runtime such as "music", "vases", "magic", "weapons" etc.  In those cases I put an ! at the beginning of the folder name so that they stay at the top of the pile for easier locating.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi