What VMs are you running and why?

My setup is primarily for media:

Supermicro X8DTH-6F, 2x Xeon E5530, 32GB RAM...

unRAID (26TB) - media storage
Win7 - usenet
CentOS - Plex Media Server
XBMCbuntu - virtual HTPC#1 (6450 passed through to tv)
XBMCbuntu - virtual HTPC#2 (6450 passed through to tv)
Debian - XBMC centralized MariaDB
Debian - Crashplan
Debian - Madsonic (music streaming)
Debian - Apache Reverse proxy

Supermicro X9SCM-F, Xeon E3-1230, 32GB RAM...

vCenter Operations Manager
OpenVPN Access Server
Debian - Unifi Controller
Ubuntu - Guacamole (RDP over http)

plus a few others that aren't used for anything...
-Linux Mint
-RHEL 6 for a couple things I've yet to start up.
-CentOS 6 with Puppet Enterprise for testing.

-Bunch of RHEL 6 instances. For Puppet Enterprise, Razor, Apache, MySQL, and a few other VMs.
-At least a couple CentOS instances. Puppet testing, and a Postgres database I've yet to touch.
-Solaris 11 - mostly just to keep up since it's unlikely we'll upgrade any of the Sun servers to 11 at work for quite some time.
-Windows Server 2012. Mostly just to play with since I had a few licenses.

Beyond that, I've got an Alpha emulator on the desktop running OpenVMS as well as Hercules running MVS.
Mines a baby

Running ESXi 5.5.0 -
Gigabyte 990FX!-UD3
32 gigs RAM
IBM 1015m card flashed to IT mode
60GB SSD for local storage

VM's that are on all/most of the time
unRAID for storage (1015 card passed through to this)
Ubuntu server 13.10 for Calibre server and whatever
Ubuntu server 13.10 for web page I will eventually make when I get off my butt

Other VM's
FreeNAS, Napp-IT, Ubuntu SAN (was trying out own SAN with LVM), Slackware, Gentoo

I need to download all the windows stuff from technet before technet ends :|