Garth Gutenberg

Lets you display a twitter feed in a sidebar widget. 
Caches last successful tweet retrieval and only updates if it successfully gets a new list from Twitter. 
Practically every element has a unique class so that it’s highly customizable via CSS.
There are various configuration options including:
<ul>
<li>Title</li>
<li>Twitter Username</li>
<li>Max Tweets to Display</li>
<li>HTML to override the View All link</li>
<li>Time Placement (whether or not the timestamp should appear before or after the tweet)</li>
<li>Time Format (uses PHP’s date() function for formatting)</li>
</ul>

GG Twitter

Aaron D. Campbell

A widget that properly handles twitter feeds, including parsing @username, #hashtag, and URLs into links. It supports displaying profiles images, and even lets you control whether to display the time and date of a tweet or how log ago it happened (about 5 hours ago, etc).
<a href="http://aarondcampbell.com/wordpress-plugin/twitter-widget-pro/" rel="nofollow ugc">Twitter Widget Pro</a>

Twitter Widget Pro

A widget that properly handles twitter feeds, including parsing @username, #hashtags, and URLs into links.

GG Twitter vs Twitter Widget Pro