I’m a Firefox user, but I used to like Opera back in the days before Firefox was available. I changed over once I discovered TabMixPlus and All-In-One Gestures, which collectively replicated most of Opera’s cool features – all except side-docked tabs, which doesn’t seem to be available in Opera any more either.
There are far too many things which like to dock with the top or bottom of my screen. Given that I use a Mac, I already have an extra menu bar to start with anyway. Computer screens are increasingly in widescreen aspect ratio, but documents read best in portrait mode. This is why most blog software (including this one) puts links and metadata at the side of the page rather than at the top, but there are still webapps out there (Google Maps being one of the worst offenders) that have a huge, wasteful banner across the top of the page.
So imagine my joy today when I found this Firefox chrome CSS hack:
The dropdown menu placement doesn’t match the tab bar location, but that’s a minor problem. I can now see Google Maps in a slightly less letterboxy format. Woohoo.
The Fifth Wheel of andrewg 
Of course, this chrome hack doesn’t work with Firefox 3. But there’s an even better solution: the Tree Style Tab extension. Unfortunately, while it appears to work smoothly on Mac, there are some rendering issues under Linux. Still worth the download though.