Tree Style Tabs is absolutely vital to me, I don't understand how people can live without that extension.
The other thing I use a lot is firefox's readability builtin (it's not an extension), which removes all the cruft and *walls from websites and makes them... readable in one click.
These two together are killer apps for me. I might consider switching to another browser (firefox isn't exactly the paragon of virtue it used to be either anymore), but the new browser would need to have these two features.
It's the hierarchical tabs that I need. If you are traversing large hypertexts you need to keep track of where you are and where you were.
Middle-clicking to open-in-new-tab together with Tree-Style-Tabs is incredibly useful in this scenario.
You can rapidly open a large number of potentially-interesting links in tabs, and then weed out the ones you don't need just as rapidly. Then wash, rinse, repeat. It's an assembly line approach.
The other thing I use a lot is firefox's readability builtin (it's not an extension), which removes all the cruft and *walls from websites and makes them... readable in one click.
These two together are killer apps for me. I might consider switching to another browser (firefox isn't exactly the paragon of virtue it used to be either anymore), but the new browser would need to have these two features.