Plugins which improve the basic security of a WordPress instance

I installed a couple of plugins on my instances of wordpress to offer some basic protection which is not available in a stock wordpress install.
First plugin is Simple Security, this plugin protects against brute force login attempts. (There seems to be an issue with the current 1.0.3 release of this plugin where browsing multipage section of the admin section eg posts, followed up with the developer for feedback).

Second plugin is Ban Hammer which allows you to block accounts from signing up using a listed domain or specific email address.