zfs is an excellent platform for a file system. Sharing it with Windows is crucial for end-users. That can be acheived with nfs, iscsi or cifs. The latter is easiest to set up, sets least overhead on the client (nfs heavy here) and least on the zfs (iscsi single file heavy here for snapshots).
Samba is commonly used for this purpose. It can integrate with AD
http://web.mac.com/davekoelmeyer/Dave_Koelmeyer/Dave_Koelmeyer_-_OpenSolaris_2008.05_ZFS_File_Systems_and_Snapshots_1.html
