Every time I get my logwatch report and see the 20 - 40 daily brute force attempts on it, I cringe. I've locked it down to a point, but ultimately I prefer convenience on some level. Limiting any one IP to 2 ssh connections every 5 minutes has annoyed me as many times as it has probably saved me. Preventing root from logging in is nice too.
Ultimately though, I wanted a way to fight back against the brute forcers.. to get a step ahead of them. From seeing the success of projects like SpamHAUS and Project HoneyPot, I know that massive group collaboration works. Of course I started thinking how I'd write it in my head. Every time... for months.
Well, once I let go of my egotistical desire to write it, I found this great project, DenyHosts, which does the same thing for the brute force scanners. I just installed it, and already it has added a few IPs to hosts.deny. Go download it, run it, and stop the annoying scanners!