Nagios/Zenoss/Zabbix Installation

I don't care which platform is installed. We have a CentOS VPS we purchased and need one of the three systems installed for monitoring. We require a GUI to add/remove services being monitored as well as provide information. We need templates to monitor the following: Port 80 response Port 53 (UDP for DNS response) FTP/21 https/443 smtp pop3 ping imap We need to be able to enter a reference ID for each check..so when it sends an e-mail that a service is down, it will include the reference ID so we can find the system in question. The templates for the above services need to be set to monitor every 5 minutes and send an e-mail alert if the service fails. Also send an e-mail when the service has recovered. We also need another template setup to use SNMP to monitor the load average on linux servers. If the 1 minute load is above 50 it should send an alert via e-mail. If it is over 100 it should send a separate alert. No recovery alerts needed. We also need this template to monitor the disk space of a specific partition. If /partition is above 95% utilized, send an e-mail alert. Finally, this is not required; however, if you have the ability to do this, include it in your bid as well as let us know. We would like three monitoring nodes setup. The first is the primary node. Excluding the SNMP monitoring as listed in the previous section, for any of the TCP checks, two or more locations have to view the service as down before sending an alert. We will keep the three systems in three different locations so a network issue will not generate a false alert. Time is important, the project must be completed and ready within 24 hours of bid acceptance.