You will want to understand which numeric format is being used so you can properly interpret the value. Windows, most of the development done with the Windows Platform SDK, and the actual constant representations are in hexidecimal. Several programs such as Office, Visual Basic, SQL Server, and VBA use the decimal represenation. For your own work, you can use whichever makes you most comfortable. The Doctor will take these one at a time.
Display is mainly an issue with fonts.
Even when you use a Unicode-enabled product such as Word 2000, you will not be able to see text in some languages unless there is a font available to support the text. When this happens, you will only be able to store the information. Input of text does get better every version, though obviously that is no consolation if the language you read and write does not have an associated keyboard yet. Regional options are in most cases a simple convenience. By choosing one of the locales listed in the regional options dialog either at setup time or afterwards in the control panel applet, all of the settings in the entire Regional Options dialog can be changed.