I watch soccer only when there is a semifinal/final of champions league, copa del rey or liga bbva. I try to watch every single world cup match, quarter finals are a must. I dont follow soccer every day and I am not a fan of any soccer club in particular(love when barca losses though).
I watch boxing when there is a huge fight but other than that... meh.
Now, MMA? i watch it more than any other sport. I guess i could say it is my most watched sport right now, and i always keep up with any news.