The best sort generally is one that you feel like yourself in iyswim.
However warm it is - you can always add more layers under it. I have a wool one that's about knee length and I wear it all the time, it's quite fitted, nice neutral dark colour and I hardly even take it off in bed.
That way whatever else I am wearing I always feel fairly confident that I'm going to look acceptable when I go out.
It is warm as well, but not overly warm, you can keep it on in shops etc.
Mind you I just bought a Calvin Klein one too and feel guilty It's disappeared from the website as it's out of stock now - I think it said it's 100% cashmere, wondering what it will be like, how warm, waterproof etc.
I do have a Barbour jacket which is nice but I don't feel right in sporty or bright coloured coats. It's just not me.
Probably warm enough but I'd want one that's also waterproof, especially on the school run! A padded waterproof coat is probably best - I got one last year which I wore all through our wet spring and it's back out again now!
Starting to look at the Autum/Winter range of coats and wondering what was best - a wool blend coat or a more casual padded (barbour) type of coat? Not had a woolen coat in years and can't remember if they are warm enough!