I tried this:
VB Code:
  1. Dim cult As String = Application.CurrentCulture.CurrentCulture.Name

  2. Dim SGR As New System.Globalization.RegionInfo(cult)

  3. MessageBox.Show(SGR.IsMetric)
To retrive the measurement system accossiated with current culture of the user. But as you may know this wont reflect the user override in Regional Settings of Control Panel.

So,
First: I want to know about any wrokaround for this, including APIs.

Second: There is a registry key, HKEY_CURRENT_USER\Control Panel\International\iMeasure, whose value is 0 when the user has chosen Metric and 1 if U.S. Reading that key value will solve my problem but i want to be sure if all the Windows have that key? I am 99.9% sure. What about you?