Probably the best way to lose fat is to eat right and lift. Cardio burns more calories than lifting DURING the exercise. However, lifting increases your metabolism to burn more calories while at rest. Since you're most likely resting a LOT MORE than you're working out, that one pays off more in the long run.
I'm not saying ignore cardio, but focus on lifting with some cardio added in.
The most important thing is diet though. If you don't eat right, all the exercise in the world won't get you ripped.