[aspiring335]

I'd be tempted to go with Assist / Bluetooth from the factory, and the aftermarket nav system. The BMW bluetooth system is really nicely integrated and extremely easy to set up and use.

I personally dislike the iDrive system and wouldn't select it until BMW sets aside their arrogance gets some people who actually understand UI design to overhaul it. It doesn't help that anyone who criticizes iDrive here is automatically branded 'stupid' for finding it unnecessarily complex. I do agree, however, that it looks good and I hate the aftermarket nav adhered to the windshield with a suction cup.

Also, when it comes to resale time my gut feeling is that today's nav systems will seem painfully archaic, more so than the other options on the list. For one, they won't be using DVD media to store maps and it will be a snap to get map updates automatically.