I've just come from a 3 Door to a 5 Door car, I did so because we are expecting a child, and I wanted to make things as practical for my other half as possible.
That said, the practical advantages of having a 5 door, even now give the car a lot of purpose already.
Front doors are smaller, this makes exiting in tight spaces easier, this also makes them lighter - seems insignificant,, but I love it now.
Got a coat? No problem, chuck it in the back without having to smother your passenger with it as you fling it between the seats.
I often put my laptop bag behind my seat as its liable to get trodden on in the front, is a little less visible in the back, and no where near as much room for it to move about, this is also far more convenient with 5 doors.
If you've ever had a 3 door car you care about, you'll understand how painful it is watching people scrabble all over your car to get in and out, its even worse when someone inevitably trips on the seatbelt and puts your door into another car/lamp post/wall. Although, the view isn't always bad when dropping female friends off at the weekend
Unless you're going for the Zetec S that looks particularly nice and sporty, I'd say go for the five door, its still a pretty car, just a lot more practical and cheaper to insure.
I had a 5 door courtesy car a few weeks ago and was quite impressed with it, an attractive car and the Zetec trim and up has loads of toys standard.
