IT Operations Management - Software Suggestions

[NaTaS]

I am doing a write up on some software based monitoring solutions for infrastructure equipment and wonder what you other geeks use.

I have used IpSwitch Whatsup Gold and Performance IT's - ProIT total management software. I want to make sure I cover most of the good products out there for either performance monitoring or performance management. Let me know if what you've used in the past and why you like it .

Thanks!