All vegetable oils are, by definition, cholesterol free.
Some, however, actually help lower your cholesterol.
All fat, whether animal or vegetable contains the same amount of calories -- 9 per gram.
Everyone needs some fat in their diet, but you get enough through things like meat, fish and dairy without additional oils.
IMO fried food is ok once in a while, but if you are watching your weight and general health it's probably not a good idea to actually fry your foods as the main means of cooking. Try steaming or stir frying veggies. Or sauteeing them in a very small amount of oil. Many pro chefs boil theirs.
When you do fry, make sure your oil is hot enough, otherwise the food will absorb oil.
Try this method for your french fries: http://www.foodnetwork.com/food/reci..._22763,00.html
Margerine and other partially hydrogenated vegetable oils (solid at room temperature), contain trans-fatty acids which are bad for you.
Here's another VERY good link: