I'm surprised to see Better WP Security winning. That thing started blocking search engine bots from crawling my site. Kept getting emails from Google Webmaster Tools saying that Google bot was denied access to my robots.txt and couldn't index the site. Found IP's for Bing bot in my blocked list too.
I use # 6
Voted for Better WP Security, seems a popular choice. I'd never really considered a security plugin until I started following some of the journey threads but now it goes on straight after All in One Seo - around a dozen sites in and never any problems.
Question: If using any of these listed, would you also still need to use the Limit Login Plugin?