1. A computer system supporting virtual desktops on server computers for access by remote user computers, comprising: a plurality of server computers interconnected on a service provider computer network; each server computer comprising computing resources, including at least processing units and memory, configured to support a plurality of virtual desktops utilizing the computing resources; for each of a plurality of enterprises, a plurality of desktop managers for the enterprise the plurality of desktop managers including: a first desktop manager assigned to an enterprise, wherein the first desktop manager comprises computing resources configured to manage virtual desktops for a first pool of users of the enterprise according to a first desktop model assigned to the first pool of users; and a second desktop manager assigned to the enterprise, wherein the second desktop manager comprises computing resources configured to manage virtual desktops for a second pool of users of the enterprise according to a second desktop model assigned to the second pool of users.