:vote: (Under certain circumstances)
Also: Don't put too much mental/emotional stock in it. When you get your ballot, just fill it out (Except for the stuff with only shitty options, leave those blank) and let God take the wheel from there.
Here's a fun little comic about preferential voting in australia, featuring Dennis the Election Koala assaulting Ken the Voting Dingo
http://www.chickennation.com/voting/
If there is an immediate benefit that you believe there is little risk of not being fullfilled, or if you're doing it purely cynically as a postponing of bad things, fine.
But objectively if you're on the left the only electoral power you can expect comes from withholding your vote, vocally and in a strategic bloc. And even then thats gonna be a long and tough process to gain anything from and the gains will most likely at some point be subverted or torn away.