What DJ Happy said. Only need for 4WD in the city would be weather so bad public services can't cope with it... in which case, you probably need to stay home anyway
No, 4WD can be nice in slippery conditions. Just remember not to engage the low range, if you have one (its usually indicated as 4L on the shifter).
I'm curious, without judging, as to why you've chosen an SUV for use solely in a city?