You have to do cardio, otherwise you just end up with a built stomach underneath a layer of fat. One of the dudes at the gym I go to is into powerlifting and stuff, but has kind of a pot-belly. He's also got some of the strongest abs I've ever seen, but theres a layer of fat over them.
Do lots of cardio to burn the fat, and then do strengthening excercises to build up the muscles and give them definition. A lot of it is also genetic, you can't forceyour body to burn fat off a particular part of your body. My girlfriends dad is a marathon runner who has a slight potbelly, and it won't disappear no matter what he does. Heredity determines the distribution of the fat stored in your body as well as where your body looks to burn fat when you exercise.
Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
-- Albert Einstein