There are several factors to consider. If you are able to commit to a healthier diet and exercise, and feel like you will be successful with a restrictive type surgery alone, then the lap band or gastric sleeve is a pretty good option. The sleeve also removes the portion of your stomach where grehlin is made, which is the hunger producing hormone. While your body will eventually compensate and start making it again, it will not be nearly as much as it was before.
If you are unable to resist things such as sweets, and don't feel you will be able to change your eating habits, then bypass or ds might be a better choice.
If you need to lose a lot of weight quickly, say due to needing knee replacement surgery for example, then again, bypass would be best for that.
Make a list of the pros and cons of each type of surgery. List what is important in your weight loss goals and compare them to the results of each surgery with your doctor. Talk to people who have had the various types of procedures and find out if they are happy with their choice, if they had it to do over, would they choose the same surgery type again, etc.