1. NFL
2. UFC
3. NCAAF
4. NBA
5. International Competition Soccer (more men, but women also)
6. MLB
7. NCAAMB
8. Tennis (majors mostly, men & women equally)
9. X-Games (both winter and summer)
10. NHL (playoffs only)
I watch the Olympics (both winter and summer) and tend to watch or at least follow along major events from Golf, MLS, Champions League, Boxing, the World Championships (swimming and track, mostly), Tour Du France, etc. but those are like once a year type things so I didn't rate them.