It's a serious question and one I'm forced to contemplate whenever I catch sight of a coat with even a hint of a ruffle. Emma has three coats now, yes? So maybe three is a sensible answer because she seems really sensible about this sort of thing - but I'm not so I'm still admiring all these pretty coats :)
I adore the green tiered Babylon coat, the red Big City Blues coat, the gorgeously retro houndstooth Park Avenue Party coat, the ruffle-edged Spiced Vanilla, Fresh Coat in Print and Out and About coats, the sweet Paddington Station coat with ruffles, rose buttons and bow pockets and the scallop detailed Ringspun Mime puff collar coat in teal. And if you're looking for something in winter white, I don't think you can get a coat prettier than the Charming Abby coat with its embroidered detail or the sweet Gumdrop Detective from Modcloth.
Okay I'm off to coat rehab now, I swear.