In the future, there will no more balloons because helium will be more expensive than diamonds:
Scientists say the world could run out of helium in 25 to 30 years, especially because a U.S. law stipulates that the country's National Helium Reserve--by far the largest in the world--must be sold off by 2015, regardless of the market price. That same law has made helium artificially cheap, to the point where one scientist estimates that a party balloon should actually cost about $100. Helium is used to cool MRI scanners and also for radiation monitors used for anti-terrorism purposes.
Read the whole thing at the Daily Beast.