As someone who actually makes a lot of cocktails at home, I can tell you what I find useful and what is just for show. I received a barware set as a gift years ago - ice bucket, tongs, stirrer, bar knife, can/bottle opener, strainer, and maybe another piece or two. Other than the strainer and the stirrer, I don't use any of it. It's for decoration and someone that cares more about having a unified looking set for that 1 - 4 times a year they make cosmos for guests.
What is useful for the person that really wants to make cocktails?
Essentials:
Shaker, normal bar size. Not one of those mini jobs. They just don't work, even for single drinks. They don't hold enough ice and they don't shake well enough to really mix ice and contents to a nice effervescent consistency. I prefer a boston style. You can just buy a regular shaker and toss in a good glass that forms a tight seal.
Strainer. Not a cheap light weight feeling number.
Bar spoon. Works better than the stirring rods and allows you to do "floats" if you want.
Paring knife. It's nice to have one dedicated to bar use. The ones that come in sets suck.
Muddler. NOT varnished. The varnish WILL come off during initial use and you'll end up with little flakes of wood varnish in your drinks.
Zester. Garnishes are an essential part of the drink, not just decoration.
Measuring glass. Jiggers are a pain, particularly the ones with handles. They're awkward. The pyrex/tempered glass measuring glasses with increments marked on the side - half teaspoon, teaspoon, tablespoon, half ounce, ounce - up to 2 or 4 ounces are MUCH better. They look like shot glasses. They don't look fancy but they work. If you get a 2 - 4 oz capacity you can measure multiple ingredients into the glass at once.
Bottle opener/wine key. The "waiter's friend" style is so much better than the winged corkscrew type.
That will allow you to make pretty much everything. After that you may want a juicer and some other odd tools ... but I find glasses and books - Dale Degroff's (sp), Joy of Mixology, Vintage Spirits and Forgotten Cocktails, etc - a better way to spend money than on odd tools.
If you bought a each of those things separately you'd probably save money and have a much better set of tools than if you bought a set. It wouldn't look like a pretty set, but it would actually be useful for making drinks. So, the question is are you buying it for a person that cares more about making good drinks or having a pristine looking set?
Buon natale.
rien