What types of cuts of meats are ideal for (beef) stew?
You want a cut amenable to stewing, which is a low, slow, wet cooking method--its a variant of braising.

These are generally tougher cuts with a lot of connective collagen which will convert to gelatin during the cooking, a part of the animal that works relatively hard in life.  These cuts are flavorful and usually (relatively) inexpensive.

One cut that is often used for this purpose is the chuck (for beef) or butt (for pork), which is the shoulder of the animal.