How can I keep Safari from re-opening my tabs from my last session?

When I re-open Safari on my Mac Mini, it keeps opening the same tabs that were open before it was quit (or before the Mac OS X was switched off). The result is that it takes too much time to be operative, especially when I restart my Mac.

In the preference panel, the "Restore windows when quitting and re-opening apps" option is already disabled, but Safari keeps opening the tabs open in the last session. I checked also in my MacBook, which is running Mac OS X 10.7.2, and that option doesn't change the Safari's behavior I describe in this question.

Is there any way to force it not to open all the tabs? I looked at its preferences, but I have not found anything that could help me. Is there any other way to disable this feature?

Quit it with ⌥⌘Q or run in the Terminal

defaults write com.apple.Safari NSQuitAlwaysKeepsWindows -bool false

This behavior is the resume feature.

Disable using Terminal

If you only want to disable resume for safari, type this in the terminal:

defaults write com.apple.safari ApplePersistenceIgnoreState YES

If you want to set the resume feature again, simply write NO using the same syntax.

Disable using TinkerTool

This application gives you access to additional preference settings and allows to activate hidden features in the operating system.