According to Microsoft the default Shell UI font is Tahoma for all Latin and European Languages for Windows XP and 2000.
http://support.microsoft.com/default.aspx?scid=kb;EN-ME;823033

We should make our controls use this system font where appropriate. Interestingly some of Microsoft's own applications, the Display Properties control panel, for example, appear to use MS Sans Serif rather than Tahoma, so we need to define what the 'correct' system font is.