If you get the minivan, you'll have room to strap in your daughter's carseat, which is always the safest thing to do. It's legal in NYC for an infant/toddler to ride without one in a taxi, but better to be safe than sorry.

On a side note, I always feel foolish being a solo passenger in those huge minivans, so of course they're almost always the ones to get me from the cab stand at LGA. They're everywhere, you won't have a problem getting one.