aerobic exercise is generally best, at least 30 minutes per day is recommended
I like to ride a bicycle, it's the most efficient method of human-powered transport but anything that gets the cardiovascular system going is good for you. Jogging, sports like soccer, lacrosse, hockey, or football, and the like are also good.
Any kind of exercise is better than nothing. Lifting combind with some cardio you can't go wrong. Just start with what you feel comfortable with then progressively push yourself a little more each day.