In reply to Alan Pierce:
I'd go with a women's fit every time - I sold my "unisex" jacket and bought a women's fit one as soon as manufacturers started making them - but I'm pretty slim, and a small men's jacket is way too big round the chest which means it gets draughts blowing through it taking away all the nice warm air (and it's also too long in the arms). I am rather fussy
I haven't actually looked at what's available recently, but my impression was that most jackets were made in both men's and women's fit these days - apart perhaps from the most technical one at the top of the range. However, that doesn't mean they're always stocked in the shops - it might be worth a look at manufacturer's websites, along with those of some of the big outdoor chains and smaller specialist outdoor shops.