For casseroles, soups, etc., I always buy the skinless, boneless ones. They have a little fat on them which needs trimming off, but not much. If I am just going to cook them plain in the oven, then I will buy them with the skin and leave the skins on, otherwise I find that they dry out. Then I will take off the skin and any fat which has not cooked away, and drain them on a bit of kitchen roll for a couple of minutes. I don't think that meat soaks up fat.