Hi Mr. Harris,
It is good if you could explain your networking plans and objective to achive. From that we can share the best practice.
Concept of networking is standard but the environment make it different. 
FYI:
My VM environments:
4x esxi 5.0, 2x2 HBA, 2x3 NIC, RAM58GB, CPU2x4x2.5GHz,
1x vCenter Std,
25x VMs (Linux & Windows)
2 VLAN (172 segment & 10 segment)
1 Firewall
1 Router
2x2MB Internet