Question : Best Network monitoring software?

What is the best, or a really good, Network Monitoring and Alerting software package?
I'm goofing around with InterMapper and it seems to be nice but for an WISP(wireless ISP) what would be the best?

Answer : Best Network monitoring software?

My favorite is Solarwinds
http://www.solarwinds.net


Neon Software to diagram/document/monitor your network
http://www.neon.com/map.shtml

What's up gold:
http://www.ipswitch.com

I like the interface of Netcrunch:
http://www.adremsoft.com/netcrunch/index.php

Argus Sofware (looks just like What's UP Gold, only for Linux - and free)
http://argus.tcp4me.com/shots.html

Cacti for Linux gurus:
http://www.cacti.net/

If you have unlimited budget - Fluke Supervision products are expensive, but good
http://www.flukenetworks.com/us/LAN/default.htm

Then there's the "Gold Standard" Sniffer Pro (couple of good whitepapers here)
http://www.networkgeneral.com/Solutions_Network.aspx

Check out the new Infinistream from Sniffer
http://www.networkgeneral.com/product_demos_infinistream.aspx

Here's a link for free Win32 ports of NTOP, MRTG, Net-SNMP, Windump and NMAP
http://www.openxtra.co.uk/products/freestuff.php