CACTI - SNMP BASED MONITORING TOOL

I have done reading on various features of different types of network monitoring tools.
I have concluded to use Cacti (freeware network monitoring tool), due to the following:

a) It is a freeware
b) You can monitor unlimited amount of devices
c) agent-less
This tool DOES NOT require to install additional agents to be installed on the monitored devices.

Eventhough CACTI can monitor basic resources like server NIC usage , CPU usage , disk space usage & memory usage on it's own, it would require a freeware tool like "SNMP Informant", to help monitor more advanced Windows performance counters like disk I/O usage, TCP & IP packet statistics. This tool can be customised to further monitor detailed counters via SNMP response from performance counters. Again, this is optional.

d) SNMP based
A feature I like about this tool is that since it is total SNMP based, it allows monitoring of servers , SNMP enabled networking devices with IP address, and basically ANY SNMP supported device. No reliance on proprietary standards like WMI.

e) can be installed in UNIX AND Windows
I was finding for a monitoring tool that can be installed via Windows, since Windows based tools would be easier to setup & troubleshoot.

Below is the screenshot of my test system using a virtual approach via Sun VirtualBox (also freeware). In the screenshot, VELAN is a another laptop I am monitoring. :