T7 Intego stuff is a bit on the pricey side of things, but they deliver excellent software. Virusbarrier is personal fave. There's not much happening here on the Mac, viruswise, but I do care about my PC based clients. Netbarrier was and still is exceptional, though it looks like the Little Snitch and Leopard's new Firewall approach are dictating new directions. Been playing a bit with Personal Antispam now, and it has a good start here. Can't figure out if this beats the 'for 7 dollar a month we'll take care of your spam' but in less than 4 month I'll probably know.
(Version 10.4.3)