The shape and form you'll develop is pretty much genetically determined, but a balanced program of weights (to build the muscle) and cardio (to burn the fat the covers the muscle and may disguise the shape) is key. Stretching is also essential to keep muscles supple and avoid injury. Rest and recovery is also important when trying to build muscle (which gives the roundness and shape).
Since I have no idea what your program is like now,or what workouts you already have, I'll just give some general observations.
For cardio, interval training is a way to burn more calories in a shorter period and make your body burn fat more efficiently.
There is no "best DVD" for these purposes, IMO, but I would recommend sticking with the strength-building weight workouts (Slow and Heavy, PS, Pyramids) for a while, then using some endurance workouts for a break.
Here's just an "off-the-top-of-my-head" example of a rotation (I am shamelessly adapting P90X for this!). It will give you an idea of how to set up a balanced program.
Strength-building phase:
Day 1: Slow and heavy chest/back with ab work
Day 2: Imax 1 or 2
Day 3: Slow and heavy arms with ab work
Day 4: stretch or yoga
Day 5: Slow and heavy legs and shoulders (though if you have the pyramids, I think PLB is a better balanced lower body workout)
Day 6: kick/punch and crunch or cardio kicks (those punches are really great for developping shapely arms and shoulders)
Day 7: stretch or rest
Make sure to get good rest (you may need an extra hour of sleep per day, or an afternoon nap) and good nutrition.
Do this for 3 weeks, then take a recovery week:
Day 1: Steady state cardio (step, kickboxing)
Day 2: a full-body, moderate weight workout (ME, Push and Pull, Supersets, PH, or to add more cardio, BC or or one of the cardio/weight circuit workouts: Circuit Max, Body max)
Day 3: stretch or yoga
Day 4: steady state cardio
Day 5: full-body, moderate weight workout
Day 6: kickboxing or step
Day 7: rest or stetch
The next three weeks, repeat the first rotation, but substitute PS workouts for Slow and Heavy. Follow with another recovery week. If you don't have PS, you could substitute the pyramids, doing each one twice a week.
If you don't feel you're getting enough cardio with this rotation, you could add a cardio session to one of the weight days, separating the two workouts (cardio in the morning and weights later in the day or vice versa).
