The old fashioned way of preserving ham is with salt and cold smoking. It is never cooked. The preservation process kills off the bacteria and changes the flavor and texture of the meat into what we think of as ham. These days however, many hams are pumped full of phosphates (preservatives) and salt water, and then cooked in a chamber filled with liquid smoke mist. The phosphates preserve the meat, and the salt water gives it a more traditional flavor and texture as well as increase the weight to hold down the cost per pound. This makes them appear more reasonably priced.
So what kind of ham do you buy? The first thing you have to decide on is the price. The more time spent making the ham the more it is going to cost. A country ham, which can be aged up to a year, can set your pocket book way back. These traditional hams are hard to find at stores and generally have to be mail ordered. They are also heavy on salt and will need to be soaked and cooked before they can be eaten. The modern produced hams, on the other hand, can be picked up, sliced and served. Of course, the best way to serve ham is warm. Grilling ham gives it the added smoky flavor and makes an excellent way to prepare ham regardless of the type. Remember to grill large hams indirectly.
Next you should consider the size. Whole hams can come up to 20 pounds, which could leave you dealing with leftovers for weeks. Not a problem if you don't mind a nearly endless supply of ham sandwiches, omelets, salads, etc. The general rule is to plan on 6 to 8 ounces of boneless ham per serving, or 8 to 12 ounces of bone in ham per serving. Hams can be frequently bought in sections. This is usually either the rounded, butt end or the lower shank end. The butt end is more difficult to carve because of the shape and position of the bone but is meatier. The shank end gives smaller pieces but is easier to carve. Of course you can always buy pre-sliced hams to make it easier on yourself, but plan on not storing it as long.
As always, if you have any questions, ask a butcher. That's what they are there for. If you buy a packaged ham, make sure to read the label. Some hams, including some canned hams must be refrigerated. A good country ham that is well packaged doesn't need to be refrigerated (the process for making these predates refrigeration) or cooked (it is eaten raw). So make sure you know what you have and how to treat it. Country hams in particular require a good deal of preparation. They are also, something of an acquired taste, so you might want to try a sampling before you spend a lot of money on one.