You may want to stay clear of Win Xp Pro as this only allows 10 shares, I know this from experience due to the network I run at work. On our old network or NT server and win98 clients we used to use one of the clients as a print server, but when we move to 2000 server and XP pro clients we had to buy some netport type print servers at about £200 a piece ($320).
I had thought about using a central store for all my music and video before, but then worked out how much storage space I would need (about 1700GB and growing) to store it all. But for the main store you would probably want to use 2000 or 2000 server.
But another thing I wanted to mention is that on the network I run we have virtual cdrom software, for multimedia titles, etc. so we don't need CD drives in every machine. This software stores the CD/DVD's as image files on the server and then these can be loaded like CD/DVD's either by clicking on the image file and "inserting" it in the virtual drive, or using a CDROM player interface that lists all of the titles, and then when one is selected it is loaded in the virtual drive and a designated piece of software is run. Unfortunately this specific piece of software comes as part of a system deisgned for use inschools, and made by a company in the UK called Research Machines (RM), and they probably wont sell or supply it to any none educational sales. But a lot of their integrated software seems to be based on other peoples software which they licence or "borrow" so there may be something available out there that does the same job.
By the way this all works on top on standard windows domain networking, with several machines using the same CD image at the same time, so this could be the way to go.
It's also good for multiplayer network games where you need a copy of the CD for each player.
I hope I have been of some help. Good Luck.
Chris.