To SPS2003 : Capacity planning and other good info
If you don't know about it, check out the Sharepoint Services Administrators Guide. Its a .CHM with good info across the board on WSS. I tracked it down because I'm migrating from a SPS2001 site with a 3GB+ document library, I wanted to make sure I wasn't asking too much of WSS. Since the .CHM Guide includes an ISP scenario with unlimited users and 10 GBs of storage I guess we'll be okay.