In truth I don't really follow any sport these days. I have an interest in some sports but no longer make the effort to remember when they may be on TV or when they may have specific events etc. That said, my top three sports that I'm most interested in would be (and specifically the events, rather than the entire sport), in no specific order:
Anything Motorsport related - but primarily F1
Rugby Union - both the world cup and 6 nations
Football - exclusively only international. i.e. World Cup and Euros (Euros being a very distant second of the two).
I also really enjoy Field athletics* but it's barely covered these days, even the Olympics coverage seems to almost completely skip it, which is a real shame as it's infinitely more interesting than watching people run (over any distance). Finally the only other sports I have any interest in is track cycling and olympic weightlifting (power lifting really doesn't interest me).
*That would be Javelin, Discus, Hammer, Shot put, high jump, long jump etc for those not familiar.
On reflection, giving it a bit more thought I think I'd choose my "top three" as being:
Anything Motorsport related - but primarily F1
Rugby Union - both the world cup and 6 nations
Olympic Weightlifting - it's just rarely covered.