SolarWinds ipMonitor 9.0 is described by its vendors, perfectly accurately, as an "entry-level IP monitoring tool".
Any gripes? Just the one, and it's more an oddity than a gripe. One of our servers has a 58.5GB C: drive with 30.6GB free. Yet one of the default monitors decided that actually it's a 30GB drive with 694MB free. This is kind of odd because the two other monitors that spotted that drive both got the numbers right - and of course it's not a big deal because we could delete the offending monitor and use one of the other two.
ipMonitor is, then, an excellent example of a system and network monitoring application. SolarWinds has thought about the GUI, and it's thought about the auto-discovery mechanism (auto-discovery is a concept for which we've all seen some dreadful implementations over the years). The price is sensible.
Of the paid-for SMB system monitoring packages on the market right now, SolarWinds ipMonitor 9.0's got to be at the top of the heap.