I've been a System admin for both a school and a business with over 50 networked devices - managing them all has been a real pain and I have used a range of tools to get jobs done.
I was stumbling along last night and came across
Spiceworks - it is a network discovery reporting and management system that is free (paid for through vendor advertising). It does everything my multitude of tools used to do and more.
It does a lot - see below. And is fairly easy to use. I have asked around and a couple of schools over here are using it to manage all their devices - particularly printers and switches.
Inventory Your Network
Network Inventory
IT Asset Management
IT Audit Software
Warranty Tracking
Virtualization Management
Monitor Your Network
Network Monitoring
Green IT Software
SNMP Network Management
SQL Server Monitoring
Cloud Computing Management
UPS Power Management Software
Run an IT Help Desk
Help Desk Software
Hosted Email Support
Active Directory Management
IT Purchasing Management
Help Desk iPhone App
Help Desk Android App
Manage Configuration Changes
TFTP Server
Change Management
Map Your Network
Network Mapping
Troubleshoot Network Problems
Network Troubleshooting