From what I understand, the Wii Fit Plus is more like an actual workout. The lady at the video game store said that you can tell it you want 30 min of cardio (or something like that), and it'll come up with a workout for you. The original Wii Fit has lots of mini workouts - so you do one exercise, then have to tell it what exercise you want to do next. So even if you get your heart rate up, it won't be for very long because you have to stop to select the next activity before moving on.
You still need the balance board regardless. The original comes with the disc and board, while the new one can be purchased separately, so you won't need to buy a new balance board.
I hope that helps!!
at 2:17 PM on Oct. 23, 2009