Are there any feature differences between Windows 7 Ultimate and Windows 7 Enterprise, or is the only difference licensing? Microsoft's Compare editions page doesn't list Enterprise, but their Windows 7 Enterprise features page seems to list the same features as Ultimate.
Looks like it is just a difference in licensing between Enterprise and Ultimate.
Interesting to note that Vista Ultimate and Enterprise did have some actual differences in functionality (namely, no Windows Media Center or Ultimate Extras in the Enterprise edition): http://en.wikipedia.org/wiki/Windows_Vista_editions
UPDATE: And here is a thread with several MS MVPs confirming that the only difference between Windows 7 Ultimate and Enterprise is the licensing model.
Windows 7 Enterprise edition is designed to address the needs of our enterprise customers who have needs around advanced data protection, enabling user productivity and streamlining their PC management. Windows 7 Enterprise is part of the Windows Optimized Desktop offering, which also includes the Microsoft Desktop Optimization Pack (MDOP) tools and will only be available to customers with Microsoft Software Assurance on their Windows client licenses.