I hate all forms of cardio and it is a constant struggle for me to do it. The best cardio (for me anyway) has been sparring (either with an opponent or just beating the shit out of a heavy bag
), rugby, and rowing machines....but needless to say, you need some form of conditioning to do those for any extended period of time hahaha. Fucking vicious cycle if you ask me, I have to do cardio in order to do my cardio (if that makes sense haha)
I used to bike quite a bit but I find it fatigues my legs if I want to get any cardio out of it, then it affects my squatting if my legs really get hit hard. I usually 'stick' to cardio that is minimal in muscular effort (elliptical, rowing machine, boxing etc.)