If you only have one storage drive, you've probably never used it or even looked at it. In the Steam Client, you can set where you want Steam to install downloads into, with it being pretty darn archaic right now and not so useful. I give you Exhibit A:
Thanks once again to Pavel Djundik of SteamDB for pointing out the new leak on Twitter, we know that Valve are testing a complete overhaul to bring it in line with their modern styling. Note: you need to opt into the Steam Beta.
It's currently a little on the broken side but you can easily see where they're going with this:
To enable it you need to open then Steam console by going to "steam://open/console", and then enter "bEnableNewContentManagement 1" to enable the feature (and 0 to turn it back off). To find the Download folders you go into Steam Settings -> Downloads -> Steam Library Folders.
Once the styling on it is cleaned up, it looks to be far more useful giving you more data about each storage folder at a glance and yup - even a bit more console like I would say. Would fit in more on a SteamPal don't you think? Desktop too of course, it actually seems quite useful to get a proper breakdown like that.
What do you think?