Run a mail server with spam protection locally
 

I have a machine on my LAN which I'm going to use as a file server. However, I have also been thinking about the following scenario:

- Collect mail from all my accounts (I collect mail from several accounts across two domains) on this box
- Run an imap server on the box
- Point mail client(s) on my LAN to the imap server

The main advantages I see to doing this are:
- I can store mail centrally and access it from more than one mail client without taking up expensive space at my hosting company
- I can run a more flexible open source anti-spam solution on the server (solid anti-spam protection that is independent of the client platform would be great for me as I could think about looking at mail over GPRS from my PDA etc.)

I would value any experiences, suggestions or general input on this.

Cheers.