Abdomen Exercises? Which ones should I do?

My favourite Ab exercises that i've done ever since I was 14 and started exercising is
1. Doing crunches with my legs resting up on something and with weights on my stomach. Just like big 10lb flat weights stacked.. To stop them sliding off when you have 2 or 3 I have a towel that will go in between them..
2. My other favourite is holding a heavy dumbell at one side, just letting it hang there, i'll lean to the side of the weight, and then slowly lean, bending just at the waist, to the other side.. You need to use pretty heavy weights with it, but if you keep your stomach tensed when lifting the weight and lowering it, it makes your obliques hard as rock.. Just don't put a dumbell in both hands as it kind of defeats the purpose :)


Oh, my other one that i've done regularly is sit on a couch or seat, put your hands under your ass for balance, then extend your legs out straight, and then bring your knees towards your chest, then extend them without touching the floor.. When you first start doing these it kills.. once you get good at them, you can load up a dumbell and hold it up & down ways between your feet.. Really pumps your lower abs down to your groin..

There my 3 staples of my ab workout.. As long as pick 3 good exercises and really go all out on them either by increasing weight or reps then you don't need to do to many more...