MOnitoring Software for Unix servers

Guys,
I need a monitoring software for my Unix servers.
Over the last couple of years, the number has increased to well over 40 servers.
All have different applications running on them and it is impossible to go to everyone of them and do checks.

I was using Spotlight on Unix.

I was wondering if you all can suggest a better one than Spotlight,
I need to view faults as they occur, create reports, sar data, etc...

Kindly respond to this mail if you have a solution or an alternate way to do this.

Jair Guerra
Belize Central America

there are many out there but...

check out nagios or cacti. these might work for you. Other then that just do some simple google searches.