This free tool developed  by Rob de Veij from the Netherlands shows you about anything on ESX hosts, virtual machines, networking and storage. Overviews can be exported to CSV for import in for instance Excel. Very handy to do calculations on resource consumption.

RVTools is a windows .NET 2.0 application which uses the VI SDK to display information about your virtual machines and ESX hosts. Interacting with VirtualCenter 2.5, ESX 3.5, ESX3i, ESX4i and vSphere 4 RVTools is able to list information about cpu, memory, disks, nics, cd-rom, floppy drives, snapshots, VMware tools, ESX hosts, nics, datastores, service console, VM Kernel, switches, ports and health checks. With RVTools you can disconnect the cd-rom or floppy drives from the virtual machines and RVTools is able to list the current version of the VMware Tools installed inside each virtual machine. and update them to the latest version.

Download: RVTools