I can confirm the Samsung F4 works perfectly in my Synology DS209.
Currently copied just over 40GB of data to it and along with it being nice and quiet (can only just hear seek noise very faintly) it has remained at a cool 28 degrees C so the fan in my NAS is barely spinning
It worked straight away with Disk Station Manager 2.3 and I updated to DSM 3.0 Beta and that's working fine as well.
Thats really cool will get 2 on monday, so I am more calm now Thanks