It depends on what you want from your program.
There are folks out there nowadays who think that very high intensity, short workouts do a lot more for the body overall. Supposedly, your body keeps burning calories after the workout. Also, you waste less (or no) muscle so your metabolism doesn't slow down. If you look at physiques of 400m runners vs marathoners, there seems to be something to this.
I don't claim to know enough to be sure of the answer. If weight loss / maintenance is the primary goal, then I argue that there's a lot to be said for focusing on diet and low-intensity cardio, perhaps combined with some weight training.
Google neuroendocrine response, tabata, and high intensity interval training. You'll find a lot of info from a lot of people. Dig around at www.crossfit.com
and you'll find lots of info on the topic also.