I leave Dashboard in the dock if there's a newbie using the computer. They usually don't remember which FKey does what (heck, I always mix up which Expose key does what). If someone came and took an item outta my dock, I'd kick them.

That said, I usually put only the most significant apps in my dock, and put aliases to all others I commonly use in a folder that I put into the right side of the dock. Click and hold and you get a popup menu with all the files in that folder. Only apps on which I need to drop files stay in the dock, because sadly spring-loaded folders don't work with folders in the dock (filed a bug ages ago). Similarly, smart folders don't show the popup, which makes them pretty useless.