We have a bungalow purchased last year (approx 120sqm floor area), it's been absolutely fantastic for us and our 2 1/2 and 1 year old. We got a 1/4 acre plot which we would never ever have got close to in a normal house and because of this the privacy and feel of the house is much nicer. It also gives us the opportunity to extend outwards and/or convert the loft should we need to expand in the future... However, having always lived in houses or flats on two levels, for a while after we moved in I did slightly miss going upstairs to bed but this wears off pretty quick.
The house was a state when we bought it so fixing it up was simple, if a lot of hard work, as we didn't have lug anything upstairs it made a small but noticeable difference! We have never worried about leaving windows open at night either (apart from for about a couple of weeks last year when there was the ridiculous scare surrounding the fox attack on the babies in london), but i suppose it depends on the type of windows you have..
Before we bought, bungalows were not top of the list of choices, but having lived there for over a year now i am very glad we chose it over the normal houses on offer, and would tell anyone to consider them equally alongside 2 story houses. As it was our first house purchase it was a bit of a gamble but we had been moving from bad landlord to bad landlord in past and it's a revelation that the only person i have to deal with or rely on now is me