I own a Wii fit and really enjoy it. My spouse and I use it together for monitoring, play some, laugh at each other trying some of the balance activities, and 30 minutes on the Wii is MUCH better than doing nothing. You can do all sorts of training to get your heart rate up, boost balance and posture (really important for your core muscles), and get you prepared for more vigorous exercise as you lose weight.
We have a blast when our extended family gets together and play games on it (even though we are all well beyond the age most folks play video games). My favorite activity after doing my routine is to work up a sweat doing training with tennis - but I have to move the lamps or they are apt to go flying from my wicked forehand