We've had the WiiFit for almost two weeks now, and I've developed a bit of a routine now, which boils down to 'start at the top of the list, work down'.
I start off with yoga, doing three poses (6 minutes). Then strength training, usually the three exercises that 'match' the yoga poses I did (4-6 minutes).
Aerobics is where most of my time goes. Basic step, because advanced annoys me (3 minutes), and rhythm boxing - just unlocked expert, which is good for 13 minutes.
At this point, I've got a few minutes left. A balance game or two (finally got through the bubble balance for the first time today), and finish off with Lotus Focus (best time, 91 seconds).