Some oft quoted ideas
Allow everyone to register to vote at 16- current law in most stes allow you to register if you will be 18 by the next election. That may be as young as 16 or as old as 18. All 16 year olds are allowed to make political contribution (Hey kids, remember sending money to the Obama team? Maybe you were a Ron Paul fan or for Romney or maybe on the McCain Train)
If prohibition won't work then a country probably needs a drinking age
Let's make it 22. Your brain is more developed then than 21.
21 or military ID?
Let's let responsible college kids have a sip.
18 with completion of alcohol safety course (required for boating and driving in many states, why not have one for drinking responsibly), 17 with diploma (or otherwise proven responsible) to allow for younger freshmen. If they're going to do it anyway, why not make it legal
There are loopholes in many states, but to keep this site FAMILY friendly, they're not being listed here.
Smoking- consensus says: Just ban it.
PS If you're reading this post while driving or operating other large machinery WATCH WHERE YOU'RE GOING!