I run an nginx webserver, PHP-FPM, XCache, and MySQL for some WordPress and CakePHP websites.
I run NSD DNS servers to manage DNS for my domains. I currently use 3 different VPSs from different providers for this.
I run a Postfix mail server to handle my personal email, and retrieve it via pop3s using Dovecot. A secondary MX runs on an alternate VPS in case the main VPS is down. I also use dkim-milter to automatically add dkim signatures to outgoing email.
I run OpenVPN for personal use.
I run Duplicity and rsync for backups. Duplicity automatically runs backups to alternate VPSs. My router running TomatoUSB and optware automatically rsyncs my VPSs to a flash drive in the middle of the night.
I wrote a script to do ping tracking and monitor various resources on the VPS. This runs on two VPSs, so they can monitor each other.
I wrote a script to capture a streaming radio show to mp3 files that runs automatically on a VPS. Then my router downloads them in the middle of the night and deletes them from the VPS. So I can listen at my convenience.