The Virtues of a good shaker:
1 - conducts cold easily [plastic is out]
2 - easy to handle when you shake it
3 - pouring mechanism is not messy

WARNING! Avoid the Boston Shaker .
This is a tumbler glass jammed into a metal shaker bottom. The problem is glass and metal conduct cold at different rates, so invariably the two get stuck. In addition, you have no pour spout - a strainer is needed. They drip. Worst of all, they encourage building a drink from the ice up - a definite NO NO.

A Good Drink must be measured out.
Shot glasses, double sided hammers,
and other generic measures don't do
the job precisely enough. Their marks are too often on the outside. You can't see through metal, and glass is refractive and therefore inaccurate.

My favorite is from OXO - plastic with one side sloped with gradations marked on the inside up the slope. As you pour into it you can see the liquor actually hit the desired mark.