I guess I'll see the best of both worlds.. my dad has the minimalist M3 and I'll have an almost-loaded 09 335i (Audio + iDrive) in December
Oh, one thing the stock radio does very well is the Bluetooth connectivity. We were up and running in about 5 minutes (never set it up before). You can even access your phonebook from the radio screen (this was a big deal for me at least). There's also a small meter on the radio screen that indicates your Bluetooth signal strength, a nice touch.
Definately a good choice going with the M3.. had I known about these deals before I ordered my 09 335i, I might've gone with the M3