P90X ab ripper for me is the best :)

Man I wish you could just wave a magic wond or something. Biggest tip you could get is about a healthy diet. Unless your at a certain body fat % what ever you have won't be able to be seen so long as your adipose tissue is covering it (belly fat). But doing the exercise people mentioned will get you half way there. But it's all about your diet to do the rest!!! Good luck and feel free to ask about any nutrition relates question!!