How Do You Manage Your Virtualized Servers?

Once you've installed the hypervisor and launched some virtual machines, then what? How are you managing or planning to manage your virtual machines and servers as they multiply (even if they're hosted off of your premises)? And what about storage -- directly attached, networked and/or virtualized? What tools and best practices are you using, and how helpful can integrators, resellers and vendors be as you try to tame growing numbers of virtual machines, virtual servers, storage resources, hypervisors and virtualized applications?