I've been tracking my workouts in a Google doc spreadsheet for a few years. After a day goes by where I don't exercise I turn the date red. Avoiding those glaring failures in my routine is a surprising motivation for me. But it also dovetails with my New Year resolution to drop 25 pounds.
As for avoiding a rut, I swap back and forth doing weights for upper body and lower body, with jogging outside if the weather is nice (rare so far this year) and playing hockey (I'm on four teams) for cardio.
I've only had five days this year without a workout!
RE: Finally Getting Back into Exercising!