This is a great plugin to block those annoying bots trying to login to the admin area. Just a shame that this info isn't really used to build a database that other users can benefit from. I see the same range of bots appear on multiple sites I maintain, so apparently nothing is done with the info provided by blocking site.
It would also be nice to have some sort of automatic "default" answer when blocking sites. When I block 50 invalid logins, I don't want to answer all these 50 questions about why I blocked it individually.
For blocking IP's just for your own site, this plugin is absolutely great!