This is a difficult question to answer because the way that exercise impacts cholesterol is complex. For starters, your total cholesterol score includes measurements of both HDL and LDL.
HDL, or High Density Lipoproteins, are your "good" cholesterol. These molecules pick up fats and remove them from your bloodstream. Consequently, increasing your HDL is a good thing. Most aerobic exercises of moderate intensity will increase HDL. Typically a person who gets a half-hour a day of moderate to vigorous exercise will see a 5% increase in their HDL score after about two months of exercising. Long term exercisers can see improvements of as much as 20% over their pre-exercise HDL numbers.
LDL, or Low Density Lipoproteins, are the "bad" cholesterol, so this is the type you want to lower. Almost any form of exercise will help one to lose weight, which usually also results in lower LDL scores. Exercise also lowers LDL directly, generally by 10%-15% over the long term.
While researchers disagree on just which exercise is best, they do agree that intensity is important. The exercise should be moderately to very intense, and should total 30 minutes a day, every day. This means finding an exercise that makes you work hard enough to break a sweat, and that keeps you moving steadily without a lot of breaks. The best exercise is the one that the patient can stick to. For some people this means signing up for a class in aerobics, spinning, Zumba, or something similar. Very brisk walking, or walking with intervals of sprinting, can work, as can jogging. The easy way to gauge intensity is by trying to converse with someone while exercising. You should be able to do so, but not easily.
Weight lifting, yoga, dance, and Pilates usually do not have the intensity required to achieve the maximum cholesterol reduction, but they can still be helpful if they result in weight loss.