When you mention your Mac server, are you using it to supply managed client (MCX) settings to your Mac clients, using Workgroup Manager? If so, you can set up a computer list (if there isn't one already). Add your Mac clients to this list. Select the list and click 'Preferences' in the toolbar, and choose the 'Login' item. Then as Leo suggests, drag the volume into the Login Items, making sure to check the box that says 'Mount with user's name and password'. The big advantage is you only need to do this once as an admin, rather that for every user.
This applies to 10.4, but is very similar on 10.3. I'm not aware of any particular issue with this over SMB/CIFS, since you may not want Services for Macintosh running on your 2k3 boxes.
If you're not currently using your Mac server to offer MCX, i'd strongly consider it. Mike Bombich is an Apple guy and knows his stuff, so that doc is really good. http://www.afp548.com is also a great resource, just search for 'Golden Triangle'.
