Anton Aleksandrov

Every failed login is counted and if configurable threshold is hit, plugin will block access to wp-login.php in .htaccess, so 
that hijackers won’t be able to try anymore and at the same time – won’t use server resources.
If the same IP keeps trying after first block has expired, it is possible to block it from accessing website completely.
Blocking visitor in .htaccess is the most simple and most resource friendly way of stopping webpage abuse and wasting server resources.
Since v0.6 plugin should also log and stop XML-RPC abusers.

.htaccess Login block

Simple plugin to block login hijackers using apache and .htaccess. Simple and resource efficient way to protect your blog. Works with Apache from 1.

Sherpah_

The Safe Private Plugin set up a members-only area on your WordPress and protect your content, pages and resources from public access. 
Only registered users will be able to browse your site. The plugin will redirect all others users to the login page of your blog. 
Deny access to unregistered users, perfect for a private website, helpful during a blog maintenance and useful for developers…
<ul>
<li>Membrers-only area</li>
<li>Members only feed</li>
<li>No template modifications</li>
<li>Fast, Safe and secure…</li>
</ul>
Author Plugin link page: <a href="http://www.sherpah.net/wordpress/plugin-safe-private/" rel="nofollow ugc">Safe Private</a>

Safe Private

A Private Wordpress, a Members-only Website, helpful during a site maintenance and useful for developers...

.htaccess Login block vs Safe Private