At work I'm trying out some network monitoring tools & management tools. With a budget of 0.
NetCrunch seems snazzy and has a nicely designed interface but I haven't looked into it much. It's expensive though - 1500 bucks for the standard version. This would be on a par with Visio Enterprise, which will also discover devices and document them.
At the moment as we have it, I'm mainly using WhatsUp Gold, though it needs a lot of work.
Other items I've looked into are NetworkView (79 bucks) which is by far the smallest.
