Michelle wrote an answer about Canada Goose Chilliwack Bomber - Women's on February 17, 2010
I actually just came back from an actual store and tried on the jackets for sizing. I agree with the other lady there saying they tend to run a bit smaller in size.
I'm 5'7, 143lbs and a 38DD-F and I found that Large was a comfortable fit, with enough space for movement whereas the Medium was definitely fit to the tee--short on the sleeves and waist.
I would go for a Large--Last thing you want is to look like an overly stuff burrito which is what I looked like in that Medium. Though, it's your call.
If you are considering the longer style like the Trillium, a Medium would work fine. The Bomber style runs smaller than the Regular lengths.
Hope that helps.