Get adjustable if you can even if they are a little more expensive because you will quickly outgrow the lighter weights. It is possible that you can lift more for many exercises you may want to consider the weight of your grocery bags, a small child, your purse, items you regularly move around. With adjustable, you can have a lighter weight (the handles are usually weighted, mine weight 5 pounds each) and you can buy more weight plates when you outgrow the weight it comes with. In the long run, it is cheaper and takes up less storage space than a new pair of weights every time you get stronger. If you can, get two sets as it makes it easier if you can load one set for upper body and the other for lower body work.