After installing Debian 4.0 aka Etch, I configured Samba to point at my domain controller for authentication, and restarted it. Then I head over to my Windows XP box and attempted to access the shares, nada 🙁

So I googled, and googled, and eventually came across a post indicating that winbind was preventing Samba from functioning correctly.

So a quick update-rc.d -f winbind remove, /etc/init.d/samba restart, and voila Samba working just fine.

Hope this post helps others.

Update: It is possible that Samba will work fine with winbind if you actually join it to the domain, rather than just using the domain controller for authentication. I may test this in the future.