I trained with one of my friends last night at the gym. i was doing crunches and leg raises and he told me the best thing to do for abs (and he has a nice set!) is to use the bench that you use for your back (dont know what its called) but you do it in reverse for your abs instead of your back. basically like hanging slightly off of the bed...because it stretches your ab muscles when you are leaning back and allows your muscles to expand more