As long as the Ubuntu packages change the settings in many packages from their upstream defaults (e.g., Firefox, everything with a Tools -> Preferences, etc.) why not change the gconf setting to make this reasonable and consistent as well?
Scroll to scroll is reasonable. Ctrl+scroll to zoom is reasonable. Scroll to zoom is a huge surprise to most users. Surprising your users is a cardinal sin in UI design.
As long as the Ubuntu packages change the settings in many packages from their upstream defaults (e.g., Firefox, everything with a Tools -> Preferences, etc.) why not change the gconf setting to make this reasonable and consistent as well?
Scroll to scroll is reasonable. Ctrl+scroll to zoom is reasonable. Scroll to zoom is a huge surprise to most users. Surprising your users is a cardinal sin in UI design.