We are considering getting an annual pass for the family either for the Zoo or the Gardens by the Bay or the SEA Aquarium - we have a six year old daughter who loves animals and plants. Which one would you recommend?

I will suggest zoo as kids love animals, many activities and events. Now they even offer shuttle services from some parts of island like Bedok. Please check http://members.wrs.com.sg/beAMemberFriendsofWildlife.html. I personally like to recommend this. As by paying some extra u all can enjoy all the four parks including Jurong Bird Park.