A lot of people do P90X for that and swear by it's effectiveness, but kickboxing has always done it for me. Your best bet, I think, would be a good, fast-paced martial art.
you could try "Crossfit" depending on where you live there should be crossfit gyms all over the place, if you do some research on them you might see videos of experienced people doing the workouts id sugguest to push that to the side because there are alot of people who have no experience that go also.
the best thing is there are heaps of people there - young,old,strong,weak. and you can compete against others and everyone is there to help you out.
the name "crossfit" pretty much explains itself it gets you fit across all ranges of things strength,cardio,power,agility and flexibility. i dont want to say much more as ill let you find out more about it and see if its for you