[Samba] NT domain or AD ?

[ataylor at netvigator.com]

Greetings,

I am using samba as a file server (very happily). I currently have a samba PDC (3.0.25) which serves files to XP and linux clients (<10). This operates using tdbsam with all xp clients being members of the NT domain. The linux clients are not members of the domain, accessing files via a simple cifs mount. UID/GID for the same user name is the same on all unix clients (done manually as there is a small number of users).

This project is also something of a hobby, so I'm considering introducing a little more complexity (for interest as much as anything).
1) Is there any advantage to making this an AD rather than NT domain?
2) Would either of winbind/pam or LDAP provide security gains?

Rgds/Alan