There is a feature of the WinRAR (for Windows) archiver I love a lot: it can be set up to skip trying to compress particular files (based on their extension (name pattern)) while including them into a compressed archive. When it comes to backing up a user home directory it saves tons of time to give up trying to compress mp3, jpg, zip, etc. files and just add them to a (non-solid) archive untouched while compressing text, xls, database etc. files being added.
Having switched to Linux I still strongly prefer non-solid compressing archivers (like zip and 7z, I mostly use 7z I have switched to even before switching to Linux) over traditional tar.gz for my own convenience reasons (tar.gz advocates use to say it is needed to save rights/ownership information and links but I don't use any in my non-system files).
But I miss the WinRAR's feature to skip specific files compression a lot. May you happen to be a 7z fan too, maybe you know the way to achieve the effect?