Aside from the seasonal shoes/hat/coat comments, I used to get a ton of: "Oh, what a pretty girl," comments. My son grew hair, lots of golden curly lovely hair, at a very young age, had long thick eyelashes and big blue eyes (all apparently attributes of female children, pft) and while we trim it now and then, we keep his hair generally longish. No matter what he was wearing (though I guess we don't always dress him in insistently "boy" colors/themes), people would tell us how pretty our daughter was. It was happening so often that I would occasionally just agree that "she" was adorable. Otherwise I would just respond, "Well, "she's" a boy, but he is awfully pretty, thank you!"
And my poor DH gets TONS of comments when he's out and about. On a side note, we don't wear wedding bands, and he's actually gotten hit on a bunch when he's running errands/going for a walk with DS, which I think is pretty hilarious. The worst, however, was when he was letting DS help push the cart in the grocery store. DS accidently bumped against an older woman's cart. She peered down at DS and asked very snidely, "Where's your mama today?" Blah. She managed to criticize both of us, and I wasn't even there!