Looking at the nice photo of the full glass roof (go to TeslaMotors.com, click on "Model S", click on "Learn More ->" just above and to the right of "300 Miles per charge") made me wonder as others have: will it be too hot? Can you see the information on the touchscreen?
How will you "close" the view above?
Is switchable glass possible for automotive and curved glass applications? (LCD built in to the glass makes it electrically controllable to be clear vs. "frosted" (translucent) or "mirror" (opaque).
If it's possible, there would be no significant weight or volume difference from standard glass. Instant control from the dash. (Fresh air is done the old fashioned way...)
That's (1) for me.
While I'm brainstorming (fantasizing?), someday I'd like to see some other electronic features:
(2) How does Google Maps get their traffic information? Internet connected cars could easily periodically report their position and average speed for wherever they are, thus enabling intelligent re-routing of other connected cars around traffic, whatever the cause.
(3) I'm used to backup cameras. What I'd really like is a simulated view of my car seen from above, showing all the cars nearby. This might be done with front, back and side cameras and real-time stitching, or with ultrasonic or laser scanning around the car. The view would show on a display, preferably one that can be seen easily while driving. No need to look over your shoulder as you're about to cut someone off with a lane change when you already know they're there. Not a replacement for good driving, but nice.
(4) Skype application in the car. Mobile ISPs don't like it, but it would be nice.
(5) Social mode: detect other nearby cars with local connectivity (Bluetooth auto-pairing? Wireless access point from your car to others?) and talk to them over your Bluetooth mike and speakers! "Man, did you see that guy cut off the ambulance!" "Do you know any good restaurants around here?" "Do you know what's causing this traffic?" "How 'bout them Yankees?" :) "Nice day!" "I like the color of your Tesla S - wanna get a cup of coffee?" It would make driving more like walking with others in public - more personable. But you could just shut it off!
I'm sure many of you have ideas, too!