We buckled on the Wii too after about a year of begging and pleading. I kind of think if it's something they're THAT excited about, it's kind of best to let them get it out of their system. That being said, we do use a timer. My DS9 typically gets 20-30 minutes a day and loses the next day if he ignores the timer. Being consistent on timer use has been a life saver for us. He would otherwise be extremely addicted.
We don't have any "educational" games, but some of them require long term strategy and planning. And some of them are just fun. Even for me! I would watch the game ratings. I've been ok, with everything under the TEEN level. And we even do have one TEEN game I think is ok (Twilight Princess). I agree with the Boom Blox and Harvest Moon recommendations.
