If an SMB is deploying a virtualization solution, you really need storage networking to get the maximum return on investment. When you think about virtual servers, some of the benefit is to be able to move your virtual machines between physical machines.
To be able to do that, the machines need to be able to see the same pool of disks. If they can't, you are limited in how much you can leverage your virtualization solution. Recent ESG research found that 81% of SMB end users surveyed were planning to acquire new network storage systems to accommodate their virtual server environments. Virtualization is a major driver of SANs because of the benefits of being able to see the same pool of information between multiple servers. So, to really maximize your virtualization investment you have to have a SAN.