I look for legroom, headroom, trunk space, 4-door capacity, off-the-lot power, power windows, locks, heated seats, aw hell... I'd say the equivalent of a Crown Vic with a massive 16-cyl engine and a smoother ride than sex on silk sheets and quieter than a comatose deaf-mute.
But it's gotta have good styling. Like a Mercedes or BMW or a Bentley. I won't have a car that looks like a 14-year old drove it through a fiberglass fabrication plant.