The only Real product I've voluntarily installed on my PC is the Rhapsody player. But when I want to listen to NPR stories or other feeds that use RealAudio, RealAlternative is my choice. Real Alternative lets you play RealMedia files without having to install RealPlayer/RealOne Player. (JetAudio is OK too.)
I tried UltraPlayer, but it doesn't handle the SMIL format used by NPR and, I dunno, was just too hip for my tired and cranky attitude.