I've been using this one since Feb of this year. It has intercepted about 4 risks.
http://free.grisoft.com/
In June I got a Belkin wireless router when Wifey got her laptop and not a single threat has been detected since then with the hardware firewall, XP's built in firewall, and AVG in place.
Negative is that AVG likes to do a complete software scan when I log on which takes forever, so I hung a spare HDD in my box and moved about 25gig of files I rarely use but can't live without from C: to D:.
There are *almost* no bad BP6s. There are mostly bad caps.
No BP6s remaining
Athlon 2800
Sempron 2000
ViaCPU laptop with Vista.(Works great after bumping ram to 2Gig)
P-III 850@100