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

chipsandtv

This widget lets you display your latest tweets on your blog. Various configuration options are available.
Features:
<ul>
<li>No need to enter your Twitter password</li>
<li>No Javascript</li>
<li>Simple but reliable caching, so your website won’t slow down</li>
<li>Various options such as clickable URLs and usernames, date format etc.</li>
<li>Supports multiple instances at the same time</li>
<li>Fully compatible with widget-ready themes</li>
</ul>

Simple Twitter Widget

A simple but powerful widget to display updates from a Twitter feed. Configurable and reliable.

GG Twitter vs Simple Twitter Widget