Network monitoring

Hi,
We're in the process of growing and as of late, we just seem to be running around putting out fires but hopefully sometime, in the near future, we want to take a more proactive approach when it comes to monitoring the network.  With emphasis on the word PROACTIVE, I'd like to come up with a list of 10 proactive methods we can implement.  We have a lot of different environments from Cisco routers and switches to ASA5505s, sonic firewalls, watchguard firewalls, hp procurves, as well as a lot of virtualization on the server side.  What are your thoughts on what should be monitored proactively and some of your favorite and/or newer tools you'd use to accomplish those tasks?  We currently use LabTech for most of our monitoring but I'm thinking we need to be utilizing more SNMP traps and such but monitoring all that might get overwhelming.

Thanks in advance!  10 things!