Don't forget about SPONG:
http://spong.sourceforge.

Although my vote goes for NetSaint.

On Thu, 25 Jul 2002, Scot Jenkins wrote:

> Big Brother
> http://www.bb4.com/
> 
> NetSaint
> http://www.netsaint.org/
> 
> Mon
> http://www.kernel.org/software/mon/
> 
> I did a talk on Mon for TCLUG a while back; my notes are here:
> http://thinkunix.net/docs/monitoring/
> 
> I tried mon but later switched to Big Brother after seeing what it can
> do. YMMV of course.
>