How can I export my settings (fonts, syntax coloring, formatting, etc.) in Eclipse 3.6, so I can use them again in another installation?
You can save the folder '.metadata' in your workspace.
This folder contain your preferences, simply restore it after a re-installation and your done.
The '.metadata' folder can contain projects/plugins specific settings, the 'core' eclipse settings are in: '.metadata/.plugins/org.eclipse.core.runtime/.settings'
Theses 'core' settings can be exported using 'File -> Export -> Preferences' too as Csaba_H said.
Settings can be exported to a file using File -> Export -> Preferences, and you can import it to another Eclipse workspace.