I'm off to do an LLM in public international law, and I want to work for the UN. I have two offers. Leiden (taught in The Hague) and Columbia.

How in the name of sweet mercy am I supposed to choose between these? Does anyone have thoughts on either or both?

Both universities have an excellent reputation.Columbia is 9th in the worldwide university ranking of 2004, Leiden is 63th, see http://ed.sjtu.edu.cn/rank/2004/top500(1-100).htm - I have to add that these ranking are not about law and you can of course question the importance of rankings.

I see that you want to work for the UN. Still, you should also consider that many recruiters in big international law firms believe that an LLM from a top US law school is the only thing that really makes a difference (UK LLMs from Oxbridge and LSE, King's, UCL may also be seen as a plus). If there is a possibility that you may want to be a lawyer in such kind of firm - in case your UN plans do not work out - you should probably go to Columbia.

Ok, Leiden is located near The Hague and has close links to institutions like the International Court of Justice, but at Columbia you will have the opportunity to sneak in the UN headquarters... If you have the financial means, go to Columbia - it's New York City!