Having spent 2 months in the States as an under 21 this year I met plenty of people my own age and the impact the drinking age there has is quite incredible really. The 18-21 age group is placed in a really awkward position, since they are getting to a stage where they are looking for proper freedom and independence, but they aren't able to attain it because the "adult world" is still very much out of reach until they become 21. As a result of this, those under 21 are still viewed very much as children and seem to be given the same amount of freedom.
This is not a problem until the reins are loosed; exampl e, I came across a group of college kids I was staying with in New York, all 19 or 20. Their average evening's entertainment would be running round the corridors like 13 year olds chasing each other and being generally manic like they'd been given too many sodding E numbers. Obviously there are exceptions, but by putting things out of reach to people when they are hitting the stage of their lives when they should be taking full responsibility for themselves ends up stunting their emotional growth.Society can't nanny people as it creates as many problems as it solves and people have to realise it's a culture thing rather than a matter of freedoms.
In any case, binge drinking among teenagers and young adults in America is worse than more or less all of Europe apart from the UK (obviously), except it has become a more underground phenomenon and there are plenty of commentators that argue a reduction in the drinking age would help control the rising problem by taking it back into licensed establishments. Thus it seems the drinking age has nothing to do with levels of alcohol consumption as the nations with the lowest drinking ages almost always tally with the lowest levels of binge drinking.
Furthermore, the short-term problems affecting city centres that are so often associated with binge drinking (in particular drunken assaults and general disorder) are almost uniquely attributed to over 21s in my experience and this is suggested by statistics.
Taken from a study on victims of alcohol related facial injuries admitted to A&E (Hutchinson, I.L., Magennis, P., Shepherd, J.P. and Brown, A.E. (1998) ‘BAOMs United Kingdom Survey of Facial Injuries, Pt. 1: Aetiology and the Association with Alcohol Consumption’, British Journal of Maxillofacial Surgery, Vol. 36, pp 3-13.) found that 24% of injuries sustained were attributed to assault and that "the mean age of all patients was 25.3 years, of males 23.2 years, and of females 29.8 years" which seems to suggest that alcohol violence is a more common occurence among over 21s hence raising the drinking age would have little impact in this area also.
Ultimately, my personal believe is that a raise in the drinking age would leave the country worse off and that our alcohol problems stem more from cultural factors than legal ones.