Network Management Systems

Looking for some Opinions From the Field of current NMS systems. We're
doing a new buildout in a new area, so I can start from scratch. What is
everybody currently using for SNMP, host monitoring, notification, ip
management, etc?

As always, the magic word is "cheap", so I'm looking pretty closely at
Nagios. I have previous experience with it, but it's not an all-in-one
which would be very nice in this case.

Opinions/Experiences?

Thanks!

yhetti at shevix dot net
Wes