Directory on Wikipedia
Free News Aggregators
Feedreader – Minimalist. Can’t discover feeds. No built-in tabbed browser. Small footprint. Works fine.
Sharpreader – requires .NET framework, feed auto-discovery
RSSBandit – requires .NET framework, opensource, feed auto-discovery, tabbed browser
Sage – FireFox extension
FeedDemon – One of the best. $30 (Bought out by NewsGator)
Integrated into Outlook
Newsgator – A great choice. $30. Integrates into Outlook.
RSS Popper Free!
Web Based (Free)
Pluck – Integrated into IE
Maxthon – Custom tabbed browser based on IE. Has RSS sidebar
OnFolio– Integrated into IE & FireFox