Feed(Aggre)gator takes a list of RSS feeds and creates a single list of RSS items from those feeds to be displayed as a widget. You can select how many items you want to display and whether you want to show the entries chronologically or you want to show the latest entries from each feed listed.
You can also opt to display the date associated with the RSS item as well as the author of the item.
<h3>Donate</h3>
If you like the plugin, consider supporting the author through http://www.brownlowdown.net/webdev/feedaggregator/#donate.

feedgator

Feed(Aggre)gator merges a group of RSS feeds into a single widgetized list.

Stefi

It displays a list of feed items from a given feed URL. You can select cache recreation frequency, the number of displayable news and whether you want publication date, time (and in which format), an excerpt and reference to the plugin homepage displayed or not. You can also choose to have a ordered (numbered) or unordered (bullet-point) list and to open a new windows or not, when clicking on the linked items. You can truncate title and/or excerpt to a certain amount of chars and can sort the itmes by date/time or title.
<h3>Usage</h3>
= Usage as a Shortcode = 
* In Posts/Pages->Add New or Edit of your wp adminstration, select the HTML tab in the entry form; 
* enter either the following (if you want to display a generic feed): 
[RSSjb feed=”replace-with-the-rss-or-atom-feed-URL-you-wish-to-display”] 
or the following (if you want to display a Google News feed): 
[RSSjb location=”replace-with-the-Google-s-location-code-of-the-country-language-you-want-news-from”] 
A list of the <a href="http://www.stefonthenet.com/2010/02/21/google-news-localization-codes/" rel="nofollow ugc">Google localization codes</a> is here. 
Optional attributes for Google News feeds are the following: 
* local: city, state/province or zipcode (of Usa or Canada news and in English only) 
* gsearch: search-words according to google search syntax. Learn a few <a href="http://www.stefonthenet.com/googles-search-operators/" rel="nofollow ugc">Tips</a> about Google search (default: none); (See note 4) 
* topic: any of Google’s topic-codes (default: Top Stories). Here is a <a href="http://www.stefonthenet.com/2010/02/21/google-news-topic-codes/" rel="nofollow ugc">list of topic codes</a>. (See also notes 3 and 4) 
Other Optional attributes: 
* filter: enter any keyword which needs to be present or avoided in the titles of the choosen feed’s items. (See Note 1) 
* num: max number of items to be displayed, when all present in the feed (default: 5. If you enter 0 all the items in the feed will be displayed) (See Note 2); 
* ltime: max age (in hours from publication) of item as a condition for displaying it (default: none) 
* list: either “ul” or “ol” to get unordered or ordered lists (default: “ul”); 
* target: either “_blank” or “_self” to get links opened in a new or the same window (default: “_blank”); 
* pubdate: either true or false to display the publication date/not (default: false); 
* pubtime: either true or false to display the publication time/not (default: false); 
* dformat: customized date format (default: none. None displays the wp standard date format if pubdate is true); 
* tformat: customized time format (default: none. None displays the wp standard time format if pubtime is true); 
* pubauthor: true/false whether you allow this plugin homepage to be displayed in the footer or not (please, say yes) (default: true); 
* excerpt: either true or false to display the excerpt/not (default: false); 
* charex: limit the number of the ecerpt chars to be displayed (default: none = all chars will be displayed); 
* chartle: limit the number of the title chars to be displayed (default: none = all chars will be displayed); 
* title: title for the items list (default: none); 
* link: either true or false if the title is linked to the RSS/Atom feed URL/not (default: false); 
* sort: either true to display the list in alphabetic order (by title) or false to display in reverse date/time order (default: false); 
* cachefeed: cache refresh for the feed (in seconds) (default: 3600 => 1h);
<h4>Usage As a widget</h4>
<ul>
<li>in Appearance -> Widgets of your wp administration, drag & drop the RSS Just Better widget to any widget-ready area of your wp;</li>
<li>Now, complete the widget form: 
** Enter a title to be given to your items list; 
** Choose whether you want the widget title linkable to the feed URL or not; 
** Enter the RSS/Atom feed URL of the items you wish to display OR 
** Enter the location of the Google News feed items you wish to display; 
** Enter topic or search keys, local (all optionals) if you chose a Google News feed; 
** Enter the frequency for the cache refresh (in seconds); 
** Choose if you want your list sorted by title instead of the standard date/time; 
** Enter any keyword which needs to be present or excluded in the titles of the choosen feed items. (See Note 1) 
** Enter the max number of items you want to display (when available) (See Note 2). If you enter 0 all the items in the feed will be displayed; 
** Enter the max age (in hours from publishing) an item needs to have to be displayed. Useful for less frequently updated feeds; 
** Enter a certain amount of chars, if you want to truncate the titles; 
** Choose whether you want a publication date/time (and what formats), excerpt (and how many chars of it) or not; 
** Select whether you want a dotted list (default) or a numbered/ordered list; 
** Select whether you want the linked items to open up in a new page (default) or in the same page; 
** Choose whether you allow this plugin homepage to be displayed or not (please, say yes); 
** Click on ‘Save’ (and ‘Close’ the widget form, if you want). 
(1) Notes on ‘filter’ attribute/parameter:</li>
</ul>
<ol>
<li>You can enter one of more words to be able to select your feed’s items by keyword. So if you write “foo bar” you will INCLUDE ONLY those titles where ANY of the two word(s) is present and if you write “-foo -bar” you will EXCLUDE ALL those titles where any of the two words is present instead.</li>
<li>You can also mix inclusive and exclusive terms as in “foo -bar” of course (it will include only titles with “foo” and without “bar”.)</li>
<li>Search is case insensitive and searches for keywords in the titles only.</li>
<li>Wildshars, quotes and boolean are not enabled for this search. 
(2) Note on ‘num’ attribute/parameter: 
The maximum number of displayable articles/items depends on the number of articles stored into the XML page (RSS/Atom feed page) of the website you want to syndicate (i.e. if you wish to display the latest 15 items and the original feed contains 10 items only, then only 10 items will be displayed). 
(3) Note on ‘topic’ attribute/parameter: 
Not all topics are set for all countries/languages. If you select a topic for a country where this is not provided (as yet?) then the “Top stories” (the default) will be displayed instead. 
(4) Note on ‘topic’ & ‘gsearch’ attributes/parameters: 
Google (not me!) allows to search by topic OR by search-word(s). The two “filters” do not work together: if topic AND search-keys are both entered by the user, then the search-keys will be ignored and no error message will be displayed. 
(5) Note on ‘Local’ attribute/parameter: 
This option is available for Google News in English limited to Usa and Canada. It allows to enter city, region or postcode for local news results only. 
Example of shortcode with all attributes and their default values for a generic feed URL: 
[RSSjb feed=”http://feeds.feedburner.com/StefaniasBlog” filter=”” num=”5″ ltime=”” list=”ul” target=”_blank” pubdate=”false” pubtime=”false” dformat=”” tformat=”” pubauthor=”true” excerpt=”false” charex=”150″ title=”” link=”false” sort=”false” cachefeed=”3600″] 
Example of shortcode with all attributes and their default values for a Google News feed URL: 
[RSSjb location=”us” local=”” topic=”” gsearch=”” filter=”” num=”5″ ltime=”” list=”ul” target=”_blank” pubdate=”false” pubtime=”false” dformat=”” tformat=”” pubauthor=”true” excerpt=”false” charex=”150″ title=”” link=”false” sort=”false” cachefeed=”3600″]</li>
</ol>
<h3>The Future</h3>
<ul>
<li>being able to view images (and media files) too</li>
<li>more feeds for more websites</li>
<li>filter by keywords in description too (new attribute)</li>
</ul>
<h3>Interaction</h3>
<ul>
<li>Would you like to see a new feature in this plugin? Please write me here: stefonthenet@gmail.com;</li>
<li>Would you like to see a broken/orphan plugin working again? Write me anyhow, I might (hey, MIGHT) find the time to give it a look.</li>
</ul>

RSS Just Better

Displays a list of RSS/Atom feed items given the feed URL and other parameters (optionals). Highly customizable.

feedgator vs RSS Just Better