Question about DC overhead.

This is a question about overhead, but bear with me for a little background.

I have been trying to figure out how to approach a solution to licensing
with my new 2003 server. I have an existing 2000 server with 20 client
license. I have 3 5-user 2003 server licenses. I am starting to see that I
have to add these licenses to the 2000 server, instead of the 2003 server,
due to the per device licensing setup.

The 2003 server was purchased because the 2000 server was being taxed by the
DC, the current user volume(~17), the file access, and the TS connections
(~10) it was performing. I intend to move the file access to the new server
which all of the users will be making their connections. The only operations
remaining will be DC and the TS connections.

Now for the overhead question:
How much overhead does the DC consume to keep track of shared fiolders,
users, groups, and computers?