I'm with zebra -- unless it's the perfect situation otherwise (and only option), then go for something with a garage. You can't leave the kids in a street spot while you go back and forth, and come winter it's going to be a nightmare, whether they're sleeping or awake. You'll go out, find you were plowed in, put the kids -- where? back in the house? standing alone on the sidewalk in the cold? -- while you shovel your way out, then get them in the car? Even if the plows came before you parked last night, there's still going to be a HUGE mountain of hard packed snow on the passenger side of your car. So unless you drive a van or SUV and your 3-year-old can climb in the driver's side and get over and strapped in on her own, that's not going to work well for you. And how will she get unstrapped when you get home?
My instinct is to say, people deal with this kind of stuff all the time. You'll learn, you'll get used to it, you'll develop a system. And that's true. But I wouldn't want the hassle.