Fluke Networks is a well known name when it comes to network testing hardware and devices. That being said, their Visual TruView monitoring software is top notch and one of the best SNMP/monitoring solutions I have seen.
I have used the competitors products in the past, namely WhatsUp Gold and others, and they don't even come close to offering what Fluke does with their product!
The way that TruView presents its information, via a HTML5 front-end applet with the visual and textual renditions of the data is superb, the dashboards are full featured and make it easily readable to even the entry level IT professionals. It helps you narrow down the problem areas quickly and efficiently, and drill in to fix the issue with little to no downtime.
From what little I've used this solution (I've only deployed it twice), it has quickly become my "go-to" for my clients when their in house IT needs a management solution, and especially when I am doing the management myself!