Choosing destination folder for downloads on a case-by-case basis
The default operation for the Mac versions of any browser does not allow this. Someone told me the keys to press to pull up the entire Finder tree and during the download process, but I have forgotten the sequence. I believe it has to do with pressing "control" as you click on something. I can't recreate what I did before.
MacBook Pro, Mac OS X (10.6.4)