The workhorse of the shaker is Kosher.  This salt is inexpensive and available at virtually every market.  If you are cooking fresh food at home and do not have a box of this then you should eat out.  Kosher, or actually Koshering salt, has a slightly flattened pyramid shape and is ideal for drawing moisture from meat.  In the kitchen it is perfect for seasoning many foods for this reason.  Some will say it isn't good to add at the table and while not strictly a finishing salt I have to admit a good sprinkle on hot buttered mashed potatoes is one of my favorite things.  That and a good grind of fresh cracked black pepper, but that's another post.

Fleur de Sel is one of the best finishing salts around.  Light and airy by comparison to its kosher cousin this salt finds itself at home on any dish.  It is skimmed from the evaporation pools before it has clumped and fallen to the bottom.  I believe it truly shines in places salt is typically unexpected.  Like dessert.  A sprinkle on caramels or dulce de leche ice cream is salty sweet nirvana.  Although a good pinch on freshly roasted broccoli is pretty darn good too.

Himalayan Pink Salt.  I have this rock in 2 forms; a slab and rocks for cooking.  The rocks are quite large as salt goes, but I have truly enjoyed using it in stocks or for boiling pasta where there is ample time and moisture to break down the pebbles.  The plate or salt block is from Steepleton's.  I have been fascinated by these salt blocks for several years and was very pleased when I saw that they carried them.  The block is more of a cooking device that imparts great flavor-- think of it as a salt griddle.  I haven't cooked anything as yet, but watch for pictures as soon as I decide which beef dish is getting the salt block treatment.

Sel Gris is a nice finishing salt that is a cousin of Fleur de Sel.  It is allowed to clump and sink to the bottom.  Therefore it is higher in moisture and takes on the characteristically grey shade.  

Hawaiian sea salt or Alaea is very tasty when used on pork or chicken.  I have even put some on homemade pretzels for that extra salty crunch.  This salt picks up the red color from harvested red clay that enriches the salt with iron oxide.  The flavor is more earthy than some salts, but really delicious on many dishes.

Smoked sea salt is another favorite of mine and can provide some smokey goodness to most any dish.  There are many varieties on the market and it can be easily made at home with some patience and a smoker.  The variety of wood will effect the flavor as one would expect.  I currently am enjoying one made with planks from bourbon barrels... quite nice.

Finishing salts become more popular everyday and frankly more expensive too.  I use them sparingly and when the dish deserves it.  I keep a grinder with plain sea salt in it and that is quite nice on most dishes I serve.  The grind and texture can be adjusted, but you can put me firmly in the "I like a little salty crunch" camp.  Not every bite, just a little culinary spark that makes even plain green beans light up.  Like everything else in the food world your taste is what matters.  Try some kosher... maybe get a bit of fleur de sel... put a little smoked salt on your oysters... this rock can be addictive and in this case, that's OK.