What is the best exercise to get a six pack?

Exercise Nutrition: You can do all of the ab exercises you want but you will not see definition of your abdominal muscles (or six pack) without losing the body fat covering your abs. In order to lose body fat you must burn more calories than you consume. But, some ab exercises are better than others. Link suggestion: http://sportsmedicine.About.Com/od/abdominalcorestrength1/a/ab_obsession.Htm?Nl=1.