Here's the latest on gzip encoding support in RSS news aggregators:

• Aggie 1.0 RC5 - supported
• Awasu - supported in 1.2 and later
• Bloglines - supported
• AmphetaDesk - no support planned until after 1.0
• bortaloo - supported
  
• Bottom Feeder - supported
• Channel Buddy - not supported - but private in-house aggregator used by "a total of two people in the world"
• clevercactus - supported
• effnews - supported
• FeedDemon - supported
• FeedReader - unsupported
• Hep - supported in 0.4
• java.blogs aggregator - no plans to implement GZip support
• Magpie RSS - supported as of 0.5
• MyWireService - supported
  
• NetNewsWire - supported as of 1.04b3
  
• Newsgator - support as of 1.2 beta.
• Newzcrawler - supported
• nntp//rss - supported in 0.3
• ping.blog.gs - awaiting a reply
• Python Desktop Server - supported as of 0.6.0
  
• Radio Userland - unsupported but Andre Radke has written a plugin supporting gzip.
• RSS Bandit supported in 1.1
• SharpReader - Supported as of 0.9.0.2
• SnowNews
• Straw - supported
• Syndirella - Simon Fell has released a version supporting gzip.
• technews - Supported
• Wildgrape NewsDesk - Support in Newdesk 1.1