Great videos, especially the guy working out to the Bruno Mars` track!
To some extent, the best cardio workout is subjective, depending your needs, capabilities, and even personality. I`ve tried many and do return to running and swimming. Also, if something`s not fun you`re going to struggle to keep exercising.
The exercises which will raise your fitness the highest are those that involve using all four limbs: swimming, rowing, and Nordic skiing. All these three will give you a phenomenal workout, both in cardio and(to some extent, weight training/definition).