I was discussing this with @ParisLiakos in IRC.
I need to be able to link to a file entity directly and display it inline just like you were making a link to sites/default/files/some.pdf. I don't want it to prompt the user to save the file like it does with file/%/download.
With this feature we could have something like file/244/download/attachment or file/244/download/inline, but we could also keep the default of file/244/download.
@ParisLiakos also mentioned:
eg like an alias
file//download == file//download/attachment
He also mentioned that there are several different content dispositions listed at http://www.iana.org/assignments/cont-disp/cont-disp.xml, but the top two "inline and attachment" are the most commonly used.