Killer app for sysadmin types

VMWare server. I’ve been using Workstation for a while to test things – I ‘discovered’ it at a Novell ATT class more than a couple years ago – but the Server product is wonderful. I’m setting up a Win2003 server as a host that will run an NT4 server (legacy domain), at least one NetWare 6.5 server and will have horsepower left over for other things, although the other things will also run as virtual machines – I want to keep the host OS as clean as possible. I no longer have to worry about drivers for Netware, etc. and as I get more Linux literate, swapping to RH or Suse as a host OS might be a possibility.