Depends on what you want to do with the server. You can use openldap to simulate some parts of the AD. There are ways to use terminal services such as what the 2X site has.
Many of the enterprise level linux distro's already have the tools you'd need and the documentation. Debian is not exactly a distro as such.

If you're referring to file based databases like Access or Foxpro, samba comes with almost any linux distro and requires no client installation on windows. Ther are a couple of gotchas when attempting to access files simultaneously in samba, but they are well documented.