This is my latest network layout. I now have port channels using the Etherchannel protocol between my physical 3560 "core" switch and a Nexus 1000V switch in each of my 2 ESXi hosts. One of my ESX hosts, ESX2, I use for testing purposes and the other ESX host, ESX1, is more or less used for my production network. I have my BES (BlackBerry Enterprise Servers), Active Directory, Exchange, DNS and web servers (ie: this site!) on ESX1. I have other devices not pictured taken from the virtual product portfolio of Cisco's....devices like ASA1000V, VSG, virtual email security appliance (ESAv) and virtual web security appliance (WSAv). My main firewalls are currently Cisco ASAv (virtual ASAs) configured Active/Standby between the two ESXi hosts.
Lots of fun!