[cninja]

I see Opera as being flexible like FF but has the speed and UI polish of Chrome. That way, I only need to use one browser.

Top feature that no other browser offers: fully customizable UI. Right click on any UI element of the browser and select Customize->Appearance. The Toolbars and Buttons tabs allow full control over the browser UI so I can move buttons and toolbars to my heart's content.

Fully customizable keyboard navigation. Customizable using the interface at Settings->Preferences->Advanced->Shortcuts->Keyboard setup->Edit. Make sure to check the "Enable Single Key Shortcuts" option on the "Keyboard setup" pane to get the most out of it. Check out http://www.opera.com/browser/tutorials/nomouse/

Fast history navigation: This one isnt actually enabled by default; set the following preference to 3 opera:config#UserPrefs|HistoryNavigationMode The history is fully cached so there is absolutely no delay between pressing the back button and viewing the previous page in history and it comes up exactly at the point you left it.