I would like to add the recommendation for an “encryption” folder (e.g. mounted container file by truecrypt)

Those flavors of folders remind me very much of the coloured/labelled folders Mac OS used to offer (and probably still does, but I haven’t used it recently) and with the popularity of tagging these days it might be interesting to explore the concept.
(Also “flavor” (sic) is one of those unfortunate words the British and Americans cannot agree on so if you can easily describe it another way I’d encourage you to do so. I wont even ask about Cyan/Turquoise/Aqua.)

Great to see Dolphin continue to make progress.

By the way I hope the folders in the different colors will all be available in the release, it’s so much easier to spot colors rather than text.

- “public” — Folder with a world emblem on it (sort of like your “sites” folder, but with just the globe, not the whole page)
- “shared” — Think of Windows’ shared-folder icon
- “reference” — Folder with a book (either closed or open).

I think a couple people have mentioned it already, but I’d also like to throw my vote in for “downloads” — maybe use the KGet icon as an example.

- Downloads / Archives
- Books / Help Documentations
- Work Projects
- Various Files / Unsorted Stuff
- Office Documents
- Shares (FTP)
- Favorite / Love
- Temporary
- Programming (KDevelop projects folder)
- Games

It is to be noted that you will never see the same hierarchy on every computers. Instead of creating all possible folder icons, Dolphin/Konqueror should allow to add an overlay to the folder icon. This will offer the big choice of icons for people to customize their folders. For instance, on a Windows family computer (one session used by all family members), a non-geek friend put the “Shutdown” icon for a folder to tell other members of the family to not delete this important folder nor open it to not mess things arround. It was not looking-like a folder anymore (hey, it was the Shutdown Computer icon) thus decreasing usability.

IMHO, Desktop and Home icons should such special folders.
A home folder is a folder too, it should look like this.
Of course, this need two variants of the home icon (home folder and web browser home page) and of the desktop icon (desktop folder and show desktop panel-button).