Once in a while I find a new tool or other goodie that immediately draws my attention and is flagged "very useful" within a few seconds. The Lync Topology Info XML powershell script from Chris Cook is one of these examples.
This powershell script will generate an excel sheet and visio sheet based on the topology builder XML. Great for inventory or for reference and since it's free, there is no reason for not using it. If I would have seen it earlier, I would definitly spoke about it on my Community Day session yesterday.
Get it here - Lync Topology Info XML powershell