apphelper
is a general purpose handler for files downloaded from the web
or presented as email attachments.
I routinely use it with
my mail reader
(mutt http://freshmeat.net/projects/mutt/) for most attachments
and my web browser
(firefox http://www.mozilla.org/products/firefox/)
for things I wish to box view and keep, such as PDFs.
Apphelper both offers to view the file with your usual viewing program
but also offers to save the file after viewing.
I cobbled this up in frustration,
as usually you get only one or the other choice.
It remembers the last save location for reuse
and helpfully makes needed subdirectories if you're filing vigorously.
It uses GNU readline for pathname completion.
The manual: apphelper.1.html.