The powerful engine, like a small starship engine under the hood, yet with astonishingly good gas mileage.
Good cold A/C that does not load down the engine noticeably.
The ability to run the windows down via the remote when I'm unlocking the car, so accumulated hot air can vent.
Auto-headlights and power windows.
Passenger-side dipping exterior mirror in R, but only when I choose to use it instead of it being automatically triggered. Useful for avoiding the curb when backing into a space.
The 328i has navigation and real-time traffic information, but I have yet to check those features out in detail. If the car can really warn me in advance of traffic snarls, I'll be really happy.