I won't even consider other browser because of this. Rated 5 out of 5 stars
I download lots of stuff. Entire runs of webcomics, image galleries, collections of utilities. I admit I was late to discovering DownThemAll -- I was used to an external download manager/accelerator.
But then I tried it. It was a real eye-opener. Being able to grab all content linked from a web page? Big time-saver. Being able to define a list of sequentially-named files to download? VERY big time-saver. And then there's the AntiContainer for ultimate leeching...
Nowadays, I simply can't work without it. I rarely fire up my (paid for) external download manager anymore. Every time somebody suggests me to move to another browser, I point out the lack of anything even remotely resembling DownThemAll's retarded cousin. The DtA team did a fantastic job, one that highlights the power and flexibility of the Mozilla extension framework.