As admins, knowing what's going on and why is part of our job. Blah blah. Here's my new list of free tools I install whenever I change companies.
- Create VM templates (CentOS for management & properly licensed Windows Server OS with the usual template stuff)
- Mgmt. server 1: IPadmin & mediawiki - document IPs, processes, etc
- Mgmt. server 2: nagios & smokeping
- Mgmt. server 3: syslog server
- RSAT tools
- SQL Mgmt Studio
- Royal TS (ok not free, but the best RDP manager I've found)
- If you are being asked to do admin & helpdesk duties: InfraDog for the DCs and vCenter
Why have three mgmt. servers? Nagios/smokeping will probably require dedicated firewall rules, and always good practice to keep your monitoring tools away from normal servers. IPadmin/mediawiki can really sit on any Apache box. Syslog should be kept separate for the same reason as Nagios, and IO loads.
With all of that, not much you won't be able to do!
One other item is a ticketing system - fundamentally required, but customizing RT is something I've not had experience with yet. Spiceworks is ghetto, but works well enough.
The other item is an inventory system that satisfies IT as well as Finance. Still something I'm searching for. Don't say Spiceworks. Just don't.