What VLAN for switch/router mgmt ports, iLO/out-of-band-mgmt, VMware ESXi etc?

Do you have a dedicated "admin" VLAN that has all the goodies in one place? Thinking:

- admin interface for switches/routers/firewalls

- admin console for VMware ESXi

- HP iLO out-of-band server (KVM-style) mgmt

Would you want to isolate those things from each other for any reason?