We use a combination of XI for presentation and Coe for scale and flexibility, including the ability to consume data from other monitoring apps into XI for common dashboards.

Nagios Core as base + PNP4Nagios for charts + aNag on android phone - is the best solution!

nagios+cacti =)

Nagios

Nagios & Icinga works well.

Nagios

Nagios works fine for us

Nagios is the right choice for me.

Nagios is Best..!

Nagios ofc :-)

nagios + cacti + aNag

Holy Moly!! All these 1 post wonders voting for Nagios. Is Nagios team _that_ desperate??!

+1 on OpenNMS rocking it for the large enterprise.

More recently, however, I'm liking Zabbix.

Have to also admit that there are a few newcommers to this poll that I'm not familiar with that I'm going to have to at least take a peek at before voting because we're talking "... of the year" here, wh/should transcend mere popularity contest.

P.S.; It would be cool if some of the fanboys would elaborate as to WHY their particular fave is the superior to the rest of the pack.

Last year Nagios, but just installed Naemon. Next generation of Nagios, fork made by the Nagios 4.0 team. My vote goes to Naemon this year.

Atletika

Naemon has been added.

--jeremy

Only choice since Nagios Kicked out Andreas, Father of Nagis 4.