This is a question everyone wants to know the answer to.
My three suggestions are:
The Sims 3: On the Water[]
This is my first suggestion because I believe The Sims Series should have boats.
New Neighbourhood Possible Names:
Shellharbour
Port Dinghy
Shearwater
The idea of this neighbourhood is to make a suitable location for what I want.
New Jobs Possibilities:
Fisherman - Skills: Fishing, Handiness
Scuba Diver - Skills: Athletic
Life Guard - Skills: Athletic, Surfing
New Skills Possibilities:
Surfing
Volleyball
New Traits Possibilities:
Awesome
Your Sim is the peak of cool. They can't put a foot wrong.
Water Lover
Your Sim love water. They have to swim all the time, they love surfing. They even have to live near the ocean.
Diver
Sims with this trait are almost certainly going to go well in the Scuba Diver career, and will be most sims at holding their breath.
New Lot Types Possibilities
Residentual
Hotel
House Boat
Community
Harbour/Port
New Things you could do Possibilities:
Swim in the ocean
Travel overseas by boat
Swap from one neighbourhood to another
Own two homes in the one neighbourhood i.e. One as the house you live in and one as a renovater/child's future home
New Objects Possibilities:
Sailboat
Luxury Boats
Dinghy
Speedboat
Cruise
Other Boat/Surf related objects
Correct what you think is wrong or how you can improve it.
The other two will be in two other blog posts. They are The Sims 3: Education and The Sims 3: Air Travel