Where should I store application specific settings?

Solution 1:

There are a number of special folders you can use, on XP/Vista/Windows 7:

• The CSIDL_APPDATA folder is the one you will likely be most interested in. Data stored here is available to roaming users at whatever machine they log in to. This is the best place to store simple configuration data. All users have write access to this (and the last) folder. Note that none of the above folders are for user-generated data! That would properly belong under the My Documents hierarchy.
• EDIT: As Cody Gray suggests in the comments, also consider CSIDL_LOCAL_APPDATA for application data that will always be local to the current machine, but is set aside on a per user basis. The data in this folder is not available on a roaming basis, so it should be data that the user will likely not miss if they log in to a different machine.

I shamelessly copied the explanation above from a good article by Karl Peterson, explaining this for VB6 programmers. Karl also has a ready-to-use class that will help you find the directories, but IMHO he's overcomplicated things this time. Bob Riemersma has a better way in one line, using the Shell object, as below. EDIT Bob's comment below explains why it's best to use late binding for this rather than early binding.

Const ssfCOMMONAPPDATA = &H23 
Const ssfLOCALAPPDATA = &H1c
Const ssfAPPDATA = &H1a
Dim strAppData As String 

strAppData = _ 
    CreateObject("Shell.Application").NameSpace(ssfAPPDATA).Self.Path 

In my opinion it's fine to continue to use INI files in these directories.

Solution 2:

See the question "Does Microsoft have a best practices document regarding the storage of app data?" for some helpful info.