There's so many questions to ask you.
Firstly, is it only you who will use the Wii?
What kind of games are you into?
Are you interested in the sensor and motion Wii offers you?
Do you care much about online, graphics, and what the system offers you?
I have both, and I barely touch my Wii, only Guitar Hero, cause I had it before I bought the 360.
Since you have a family, it's a good idea to get a Wii though.
But you should keep both, because they are a great combination
It's personal preference so I prefer the 360 any day.