Voting Right
  
Voting. You get to do it if you own common stock. And the votes are kind of unitary, meaning that you basically get one "say" in things, which comes in the form of electing the board of directors. It's the common, not the preferred or the bondholders or big vendors or partners who elect the board, nor is it dead people in Chicago.
Yes, there are proxy votes with major initiatives that common shareholders vote on. But usually, the board aligns one way or another with those votes, and shareholders just line up behind them like lemmings to a slaughter, and vote whichever way the board tells them to vote.
Some companies have super-voting stock, shares which carry multiple votes per share, but also have the identical economic ownership stake in the company.
See: Super-Voting Stock if you care.