Smeags on 18 April 2008
I have a little sister around the same age of your niece. She loved Melee and played it with me all the time. Heck, she and I played SSE together as well. Good times there.
However, she also loved Super Mario Sunshine and Galaxy, and even though I told her it was too hard for her, she got all the way to Windfall island without my help in Wind Waker, which impressed me. ^___^
So I'd go with Brawl, it's a blast to play with anyone, and a lot of the modes are now Co-op.
