iTunes (Mac OS X 10.4) Full feed support. Supports auto-discovery via RSS icon within Safari. Enclosures are downloaded and playable. http://www.apple.com/itunes/download/
Juice (Windows XP SP2) Full feed support. No auto-discovery support. Enclosures are downloaded and playable (if a media format). PDF format is not playable from within Juice. http://juicereceiver.sourceforge.net/