How Short Can You Write Fizz Buzz? (hungtran.co)

For me personally, the sweet spot between readability and compactness would be one of the first examples:

  for(var i = 0; i <= 100; i++){  
    var out = ''
    if (i % 3 == 0) out += 'fizz'
    if (i % 5 == 0) out += 'buzz'
    if (out.length == 0) out = i 
    console.log(out)
  }

I liked my 4 (non boilerplate), readable lines in nemerle -

https://gist.github.com/vai/4647768