Resistance is futile.
It doesn't matter. You're going to be running a Linux box one way or another.
Although the whole "client vs server" thing is an entirely arbitrary line anyways. We Unix users just appreciate that principle more fully. Ars had a recent rather silly article where some Mac user decided to build a game rig with some space inside for drives and declare that a NAS.
ANY machine with an extra drive bay can be a file server. With USB, you don't even need the internal drive bay. Just hang it off the octopus somewhere and share it. Acquire and setup an automated copy mechanism (or not).
You don't even need extra storage. Just share a folder on the internal drive you're not fully exploiting. This has been an accessible feature with a shiny happy interface for 20 years in Windows. Any machine on the network can host stuff. If you have "small important stuff", you can copy it onto any device connected to your network. All of my HTPCs have spare space because spinning rust has been big for a long time and the OS overhead of an HTPC is tiny. So they all have a "local backup" folder where partial backups of the home cloud reside.
It's a very mundane idea in Unix to have your own private cloud with "drives" hosted wherever. The distinction between local and network storage is functionally non-existent. My Linux boxes have hosted shared storage for all the other machines in the home network since the 3.1 days. New "folders" like Videos and E-books get added as technology changes.