I usually carry my laptop everywhere and do work on it, but I do also need to work at my desktop PC, so I need to synchronize the files on the two machines. I have used several sync tools in the past, ranging from simple commands like
rsync to utilities like Krusader, which includes a way to synchronize directories on different machines. Recently I started using Unison.
Unison can synchronize files between Unix, Linux, and Windows machines; for example, you could synchronize a Windows laptop with a Unix server with the same ease as you would synchronize two Linux machines. You can use it with any two machines connected over the Internet, and it can use an encrypted SSH connection for extra security.