Family of 3 going to spend 6 days in Amsterdam in May. Would you recommend renting a car or is it easier to use public transportation. We will be staying in the city and want to venture out on some day trips.

A car would be a burden in Amsterdam. You would have a terrible time finding a place to park. Public transportation is easy and convenient. Even if you want to take daytrips, take a train.

Oh dear, a car would be just awful within the city, imo! I would definitely plan to go on foot and the various public transportation (trams, trains). Even for daytrips, I'd plan to take the train.

Amsterdam has to be one of the worst cities for having a car. Even walking can be a challenge with all the people riding bikes. I can't imagine driving there, and I've driven in Manhattan, San Francisco, and Brussels.

Parking costs a minimum of about $25 a day in Amsterdam, one of the least car friendly and most walkable cities in Europe - also excellent tram system and boats on canals. Day trips are easy by the superb Dutch rail and bus system.
You may want to rent bicycles instead for Amsterdam.

No car in Amsterdam! You can very easy make day trips by train.

I'm not sure i'd even recommend bicycles until you are on the outskirts, unless you are an urban rider at home.

You can't believe the number of bikes and the skill level of people riding them. My observation was... unless you can ride while wearing a tight skirt & high heels, smoking a cigarette, holding an umbrella, and talking on your cellphone... you've got no business riding a bike in the heart of A'dam -LOL.

To take a train out somewhere, then a bike tour from there, sounds good though.