Unison is a wonderful tool.  Cygwin is a wonderful tool.  Windows is the dominant desktop platform.  Synchronizing two PCs with Unison, where both run Windows is possible, with the aid of Cygwin.

Unison+Windows+Cygwin is NOT obvious to set up.  Here's what I did:

TiddlyGrande is a plugin for TiddlyWiki, adapting it to store its data in a SQLite database.

I still use (and love) my Audiotron.  The facts that it accesses files via SMB and does not require a TV to operate it are the chief reasons.  Setting up the Audiotron can be an epic task.  Here's a checklist to try when you get "Error accessing share" when you search for files: