Other than the (usually) inherent reliability of new cars these days, I think ease of entry/exit, comfort (especially over long distances) and reasonable economy are the only musts for me. Oh and a dual clutch auto rather than a conventional slush box (but that would be overlooked for a “omg I’ve gotta have one!” vehicle.
S/S annoys me, especially in crawling traffic jams, I always turn it off. Unless I set off at like 3am I’m never on a dual or m’way quiet enough to use CC ( though I’ve not had ACC yet)
Decent stereo is always a plus though.