Technically I don't think Canada has proportional representation. If they did, their results would be even better than they already are with their first-past-the-post parliamentary system.
But for the US, we could definitely use something like proportional representation to shake things up and allow some new voices and ideas to get into the elections. More variety of voices should be able to speak without fear of becoming a "spoiler" on accident. Another idea could be runoff or instant runoff elections.