You should try Mandriva where KDE is top priority (the default desktop environment). They have, in my opinion, the most polished and usable KDE4 available, they did it in the past with KDE3 they keep up with the latest KDE.

mencoder and one of its GUI frontends, it is all you need really, audio language selection, subtitles, lots of video/audio codecs, libdecss, etc, etc.

It is a swiss army knife.

I own the Neuros OSD, which is compact and looks good, simple to use and powerful, however, by todays standards it is a bit outdated, without support HD videos, MKV format, H.264, etc.

It would be fantastic if they did a Neuros OSD Reloaded, with support for new codecs and features (more powerful hardware), but with the same form-factor, this new thing is not as attractive as the OSD, and for what it is (a media PC) I think they would need to add more value.

I think Samba is an excellent replacement for windows server for simple filesharing, is usually easy to setup and some distros even drop in powerful GUI configuration tools.

I have used samba in a small office (around 10-15 office workers), with a few shared folders (around 5 GB of documents), at first the company didn't trust our use of Linux, they had a windows 2000 server which was badly managed (and filled with virus/malware and being used as spam relay), we gave them a 1 month complete guarantee that the system will keep up without any problems or we give their money back and install w2k server back.

They are quite happy now as once of properly configured you don't need to mess with it, we even added virus scanning (via clamav and hourly cron, samba clamav plugin taked a noticeable performance hit and was not straightforward to configure) and reporting via email (plus the email system running on the same server).