i've heard running and swimming...but just curious.

stairs man!

Any aerobic exercise for more than 40minutes everytime you do. Just do thrice a week, that will be more than enough.

any cardio where you can use as much of your body as possible..efx(elliptical) running swimming. Whats important is to do it in intervals...really intense for 30sec then moderate for a 1 1/2 mins back to really intense for 30 sec. Do this for atleast 20 mins at a time and the fat will melt right off.

3 simple meals a day, cardio, and light weight lifting

Cardio and strength training. Any cardio activity that you enjoy that gets your heart rate up. Lift weights to build muscle, burn fat, tone up.

Swimming is best. As buoyancy will take the stress off the back n knees etc...
Wherease movement of limbs with abbression to watter will make them leaner.

eat less

yes any cardio really, walking is good too.

I would say there is no best exercise.
the key is diet diet and exercise.
You need to eat 5-6 small meals a day. Eat some protein with each meal! Cut out all refined sugar!!! Also add more fiber. The fiber and protein will fill you up, helping you to cut down on your unhealthy eating. Also by eating more than 3 meals spread out through the day you will kick your metabolism in high gear. Here is a general meal for a day:
Breakfast: 2 poached eggs
whole wheat toast
1/2 cup fruit
Snack: Cottage Cheese with veggie
Lunch: Turkey, lettuce, tomato, whole wheat bread sandwich
1/2 cup fruit
Snack: Protein Shake
Dinner: Turkey Burger ( no bun )
Side of brown rice
Side of Broc.

Then exercise regularly 4-5 days a week. Do both cardio and lifting. But on days that you do both. Do lifting before your cardio and you will maximize your fat burn. Cardio can be a sport: basketball, soccer, football, anything with losts of movement. Golf is a no no.
So Example :
Monday - 30 mins lifting then 1 hr cardio
Tuesday - 1 hour lifting
Wednesday - Rest
Thrusday - 30 mins lifting then 1 hr cardio
Friday - 1 hour lifting
Saturday - Rest
Sunday - 30 mins lifting then 1 hr cardio
For exercises check out:
http://www.xercisefactor.com
They have hundreds of exercise video clips
Also check out the XGen to randomly generate a workout routine. You have to sign up, but it is free.

Fast weight loss always indicates that you're doing something dangerous to your body. It will try to recover, and you won't like the results.
Pick exercises that you can sustain long-term, not something you think you can do for a few weeks to 'lose weight fast'.

Running,treadmill, cycling...do at least 35-40 min everyday