System.appDataPath

Function/Meaning
User's home directory path
Type
Property of System class (read-only)
Description
Represents the path to the user's home directory. In Windows, the folder represented by AppData in the registry key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders is returned. If this folder does not exist, it returns the same folder as System.exePath.

This is usually as follows:
For XP
C:\Documents and Settings\<username>\Application Data\ (The C: part varies depending on the environment)
For Vista, 7, 8
C:\Users\<username>\AppData\Roaming (The C: part varies depending on the environment)
If the registry key (see above) could not be read for some reason
It will be the folder where the KiriKiri executable file is located (System.exePath)
See Also
System.exePath
System.personalPath