This is one of the main reasons I am making arrangements to get an Ipod. I am paying to "upgrade" to Idrive and navigation but I lose the ability to play MP3's in the process. Then adding an overpriced cd changer won't make any difference either (unless I ultimately upgrade the changer at a later date).
Even though the upcoming Ice-link from Dension is expensive, overall I think it will be a better solution for playing mp3's. Not to mention that my mp3 collection is encoded at 256kbs variable bit rate (so I only get about 50-60 songs per disk anyway - but they truly sound CD quality).
2008 BMW 535i Space Gray, Black Leather, Dark Bamboo Trim| Sport Automatic with Paddles | Sport Package
2008 BMW M5 (gone, but not forgotten) Space Gray, Silverstone Merino Leather, Madeira Walnut Wood Trim | 7speed SMG | All options
Mods: Corsa Exhaust | RPI Ram Air Intake | H&R Sport Springs | Rogue Engineering 12mm spacers