It would be great if NSIS could define constants in the scripts as !CONST <name> <value> or !DEFINE <name> <value>.
This would me e.g. allow to change my version numbering in the script with one chane instead of looking through the whole script, and forgetting some occasions.
During compile time these, constants would just be replaced by their value, not enlarging the resulting .exe at all.
How does this sound?