What is the best and easiest-to-manage Linux OS / POP / SMTP server for a novice Linux administrator?

I am a novice Linux server admin (I can us SSH, vi, cron, and understand config files), but I am willing to learn. However, I do not have hundreds of hours to research and learn all the ins-and-outs of Linux. I need something fairly turnkey:

What is the best server software that will do all or most of the following:
- POP3 server
- SMTP server
- Webmail server (with good standard features, like WYSIWYG editor, attachments, etc.)
- Web-based end-user configuration tools
- Anti-virus
- Anti-spam (blacklists and whitelists & RBL support required, spam filtering logic a plus)
- Authentication data stored in a database for easy management.
- POP-before-SMTP authentication

Similarly, I need to pick the best Linux OS to run this puppy on. I would like an OS with a wizard install, and one with adequate security for a publicly accessible server.

Last of all, it would be great if all of the above would be freely available for commercial use.

Thanks for your help!

How can I transfer a ton of data over a network without setting up a home network?

There are multiple computers on a network, however they're all directly connected to the router. Basically there the Internet->Modem->Router->Direct connections to multiple computers. I can see the multiple computers via the DHCP table on the router (192.168.1.1), and I know for sure if one computer is running some server software (Apache for example), then the other computers can access it just fine by typing in the internal IP address (192.168.1.x), and I'm pretty sure port forwarding works fine. Most computers run Windows XP, however the computer that has the ton of data and the computer that will get the ton of data both run XP. And I don't want to set up a home network, I just need a direct connection. I'm thinking there's possibly some server software where when someone connects to it, they can get the data. Either way, what should I do to transfer the (at least, probably much more) 2gb of data? I can't burn cd/dvd's. The network is small and secure, so security is not an issue.