Mailarchiva - a freely available, Open Source, MS Exchange compatible e-mail retention system. I haven't downloaded and installed it yet, but I will soon!
More Mac Games!
MacGamesAndMore.com has oodles of freeware games and applications - my faves being Neverball - that venerable old Linux game, and Linium, a new twist on the old game of Jezzball.
Mac Antivirus - ClamXAV
This has a simple GUI, and all of the functionality you need to keep your Mac virus free. Except for automatic scans. And on-access scanning. And automatic updates. Alright, its pretty basic, but compared to other Mac antivirus offerings, this one ROCKS. Oh, and it's free.