GNU IceCat and file managers
There's no shortage of essentially identical Mozilla-derived browsers in Linuxspace now. Firefox is the official Mozilla product. Two better known variations are Iceweasel--a Debian project that replaces the not-really-covered-by-a-free-license Mozilla branding stuff in Firefox with really-covered-by-a-free-license branding, and Swiftfox--which offers processor-specific optimized compiles of the Mozilla code.
Perhaps a lesser-known variant (as of this writing) is GNU IceCat. IceCat is very similar to Iceweasel in that its main purpose for being is to remove the non-libre Mozilla bits from Firefox. It goes one step further than Iceweasel in its pursuit of libreness in that it redirects its add-ons explorer to a GNU-maintained list of add-ons that are fully-libre. Don't worry--you can still install any add-on that you can in normal Firefox by visiting Mozilla's add-on site. Seems like a winner: promoting libre software without limiting the use of proprietary software.
However, more interesting than the above for me is something I've found to be case with the latest version of IceCat that is not the case with the other three. In any of the other three (or four if you count hand-installing the official Mozilla binaries rather than the Ubuntu and Debian packages), no matter what I've tried, I have not been able to tell the browser in the downloads dialog to "open containing folder" using the file manager of my choice. Whatever I've tried, they all insist on opening folders in Nautilus. However, IceCat has a file: application type with which you can set the desired file manager just as you might with any other type. And there was much rejoicing.
The weird thing is that I seem to recall that the file: application type was present in older versions of Firefox--e.g. as included in Jaunty. So I don't know if the current lack of the file: type is a temporary abnormality or the sign of things to come on all fronts. Whatever the case, IceCat is my default browser on my Debian machines because I tend to use a custom Openbox/Thunar environment most of the time. It not my default on Ubuntu because it--along with Swiftfox and the binaries directly download-able from Mozilla--does not respect your system font rendering settings. (It's always something, isn't it?)
There's a PPA for Ubuntu users and deb packages for 32-bit Debian users if you wanna give it a go.