I see what you mean. I'd certainly agree nav is nice, but not necessary. This will be my first car with one built in, though I've driven a number of rentals with add-on units.
I also like planning the trip in the advance, which is why the Google/Mapquest download to the car nav seems like an interesting feature. I'd always wind up with a page (or two, or several) of directions, which itself is a problem to refer to, especially at night.
I like having the distance to the next interesting event -- kick back for half an hour, or it that next turn coming up in three minutes? Navs I've had in rentals can be more or less good about this; sometimes they have too many trigger points for every road that merges with the freeway.
But I should stop hijacking the advice thread; we can take up nav debates in the tech forum.