These are all good methods of cardio... i used to swim in highschool and i can tell you that the fat definitely melted away like no other... I also tend to stay away from the ellipticals because i feel like i'm not doing anything, so I tend to stick to running.
One thing you have to know is that you can't target one area and lose fat from just that area. When your body creates fat, it distributes it equally to every part of your body (unless you drink a lot of beer, then the cortisol creates stomach fat). Burning it works the same way, you'll see overall fat loss rather than fat loss in just one area. Doing crunches will not burn the fat on your stomach.
Also, for the most effective fat loss, you'll need a modified diet. I'm no dietician, but I've had my fair share of experience with different eating strategies and I know what works. PM me if you want some advice.
Good luck with your fitness goals!