I'm trying to adhere to Windows standards as much as possible. And registry is the Windows standard to store configuration.
using registry make coding simpler, but because of this, registry is getting bigger and bigger every day. And that increases to time to bootup pc, switch WinXP user etc. And makes every things slow if you have low memory.
It also make it difficult to migrate a usersettings for one pc to other, taking backups etc.
You can do almost every thing using files (or subdir/files) in "All Users" profile and current users "Application Data" dir.
Use of registry can be limited to store things like Application Install dir for upgrade. And unavoidable entries like file/protocol association, ActiveX control registration etc.
I dont know why open source developers not getting this message. Going after MS recommended registry only reduces the freedom users have with out it.
You can get "Application Data" or "All Users" dir by
using register entry HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders\AppData
using %APPDATA% and %ALLUSERSPROFILE% env var
or using SHGetSpecialFolderLocation API