Storage availability and data transfer rates are so
much better than they
once
were. I can't help but feel that at some point the
best formats are going
to
encapsulate both scanned images and raw text - the
images will be as
faithful
reproductions of the original as possible (greyscale,
and including full
colour where necessary) whilst each page also has a plain-text transcribed
version attached.
Adobe Acrobat does that for ages...