Tungsten has a very high density: at 19.3g/mL, it's the same as gold. Combined with its fairly low cost and low toxicity, this lends it to use in weights and bullets.
Tungsten is used by some organisms. Some bacteria incorporate tungsten into enzymes used to oxidize and reduce compounds in the cell.
Tungsten has the highest melting point of any metal. It is used in incandescent light bulbs for this reason, and also in electrodes for welding. However, because tungsten will oxidize in air, more inert high melting point metals are used in crucibles, like platinum or tantalum.
Tungsten carbide is an extremely hard substance used in machine tools, which in turn are used very widely in industry. Since the tungsten carbide is bound together with a small amount of cobalt, this is also known as "cemented carbide." Cemented carbide tools can easily work steel. The "high speed steel" used on softer metals also contains tungsten as a major component of the alloy.