For me, it's the Hill Start Assist. If your stopped on an incline, the brakes will hold in place for about 2-3 seconds after being released, allowing you time to accelerate without it rolling backwards. A great tool for driving in SF.
I ordered my 2015 Ruby Red GT Premium Convertible on August 26, 2014 and picked her up on January 8, 2015, here in Sacramento, CA. She's sporting the 50th Anniversary Package, Manual, 3:55 axle, Navigation, and Adaptive Cruise Control.
A fun little run is Highway 49 between Placerville and Auburn. it should be nice and green in the foothills, and the road has a few tight curves to put your pony to the test. :)
I picked up a Ruby Red GT convertible at Harrold. The Inventory Manager there was awesome throughout the whole process (ordered August 24 - pick up January 8)
I'm in the process of setting up my first major road trip. Driving to SF, making a left at the Golden Gate and heading down Highway 1 all the way to San Diego, with pit stops in Monterey, Santa Barbara, and Long Beach.