Johnny Zhang
Many of us believe "vmware -v" will show you the current version of your ESX server (With all the patches applied). This is actually not true. This command only shows the version of a component.
In ESX 3.x "vmware -v" will show you the version number of "VMware-esx-vmx"
And in ESX 4.x "vmware -v" will show you the version of "vmware-esx-vmware-release"

In addition, vCenter will show the version of your "vmware-hostd"
Please keep in mind those numbers can all be different.