To chime in bit on FreeBSD, going Linux -> FreeBSD can be relatively painless, and FreeBSD will be a good place to stop if there is no further need of performance/purity/cleanness.

The was a time it was the only blessed BSD distribution for Java, unicode support has been pretty good for years, the ports management is easy and forgiving, documentation is generally clean and complete, help resources have a polite and professional feel.

In general there are stronger alternatives for a production server (OpenSBD definitively) but it's a very nice environment for a workstation or development server.