Introducing SharpReader
Luke Hutteman: handles all RSS versions, modules like dublin core, content:encoding, xhtml:body, etc. ... RSS Auto-discovery ... and last but not least, for items that include the full html description, sharpreader lets you expand a headline to view links and responses to/from other posts in other feeds. This allows you to read posts in context, and will show related posts together. [via Phil Ringnalda]
I really like the related posts feature.