I'm quite fond of this for quick statistics for my Economics course; http://www.tradingeconomics.com/ Although the CIA World Factbook; https://www.cia.gov/library/publications/the-world-factbook/ is my favourite if I have to supply a reference without checking back to government or private statistic sources.
There seems to be a lot of knowledge that LessWrongers have which is fairly awesome, but not particularly well-covered on Less Wrong.
What other sites do people recommend?
I originally came to LW through HN, and Paul Graham was somewhat influential on my early high school thoughts.
I've poked through these a bit on recommendation from other people, and they seem ridiculously useful.
If you want to be super nice, could you link to some of your favorite posts/articles?