What exactly is your goal with your abs? Squats, deadlift, and even the standing tricep pulldown will work your abs, but only in an isometric way. You do need some isokinetic training with abs as well to make them stand out. When you diet down, your abs will show, but to get the "relief pattern" of abs standing out, they have to be built up a little. That means some resistance training with weight. Bear in mind that this will increase your waist size a bit. Normally, you'll find a balance between high-reps and heavy weight to which you respond the best.