For $REALJOB I use it for Secure Database Servers (GELI and MySQL), Web Servers(Apache), DNS(TinyDNS & DNSCache, Mail(Postfix), Monitoring(Nagios, Cacti, Smokeping, NfSen), and Jails for running creepy PHP apps. We see a decent amount of traffic, 60k+ mails/day on the primary machine, 6 million web hits across 4 machines (2 in each datacenter+2 datacenters to give us the redundancy we like). All running FreeBSD 7.0
For home: ZFS for my file server, web, mail, dns, etc. All running FreeBSD 7.1-PRERELEASE