+1 for the adaptive cruise control in fast but varying speed traffic. The variant that my Hyundai has is also really pleasant for stop-and-go traffic, too. As the space shrinks below the minimal set, it'll basically progressively slow down all the way to the point of coasting for quite a while before it finally comes to a full stop (if the traffic hasn't started going yet). A small thing, but since cruise control only disengages if it comes to a complete stop, it in effect makes for a really pleasant stop-and-go commute as it very rarely has to come to a complete stop and disengage along the way. Also has the secondary effect of drastically improving my gas mileage vs. when I manually drive the same commute.

My previous experience with adaptive cruise control with another manufacturer wasn't nearly as polished, so I didn't think much of it when I bought the car. But it quickly became one of my favorite features!