Well, yesterday I got so disgusted with Firefox v10.0.2 that I decided to see if someone had "fixed" it. (I'm referring to the often seemingly haphazard download locations.)
Today I can report that although not 100%, as it occasionally appears to glitch, there is an add-on that mostly works. I'm of the opinion that it makes Firefox usable again.
Needless to say, I recommend this add-on. If you daily download hundreds of files into organized subdirectories on WinXP this add-on is a requirement if you don't want to have to verify the file is actually saving to where you intend on each and every file.
I actually created an account so I could write this "review". It is my hope that some Mozilla developers take notice before they make some other modifications that tend to impair usability.