And don't forget to change the SID of the computer after cloning:
http://www.symantec.com/business/support/index?page=content&id=TECH106823
Definition:
In the context of the Microsoft Windows NT line of operating systems, a Security Identifier (commonly abbreviated SID) is a unique, immutable identifier of a user, user group, or other security principle. A security principle has a single SID for life, and all properties of the principle, including its name, are associated with the SID. This design allows a principal to be renamed (for example, from "John" to "Jane", without affecting the security attributes of objects that refer to the principal.
Problems with the same SID on two or more PCs:
The problem with duplicated SIDs in a Workgroup of computers running Windows NT/2K/XP is only related to different user accounts having the same SID. This could lead to unexpected access to shared files or files stored on a removable storage: If some access control lists are set on a file, the actual permissions can be associated with a user SID. If this user SID is duplicated on another computer (because the computer SID is duplicated and because the user SIDs are built based on the computer SID + a sequential number), a user of a second computer having the same SID could have access to the files that the user of a first computer has protected.