Does VMWare ESX server have anything built in that I can view CPU, Memory and Network utilization? We have a single VMWare ESX server that we are trying to understand better how our VM's are performing and what changes we might need to make.
The VSphere fat client and web client both have this; it's point-in-time, showing you current numbers. If you need to track that, you'll need some sort of monitoring suite. VRops, VeeamOne, SolarWinds - heck, anything that can speak SNMP can track whatever OID you point it to.