Well...Starting by the end...
I use alax ntfs links
, mentioned at the DC thread. It's quite simple to use, basically, it's drag-and-drop.
Now... About soft links and hard links.
[please someone correct me if i'm wrong]
Soft links work for folders. They allow you to have the same folder linked in 2 different places. This means you can have the contentc on "c:\one folder" inside "c:\another folder", and when you change something iniside one of them, you're actually also changing in the other one. There's a small quirk: when you delete the original folder (the one that isn't a link), the link has to be deleted too.
Hard links work for files. These allow you to have 2 links for the same file. This means you can have the exact same file in 2 places at the same time, and when you change one of them, you're also changing the other one. A file will disappear when all it's links are deleted.
These are useful in several situations. I use them mostly for keeping stuff easly accessible in my desktop, while keeping the files and folders in their correct tree organization.
In your situation, you could make soft links for each of the folders in "current user" to "all users" and so, they'd appear on both places at the same time.