In Canada the "workers party" would be the NDP (third largest party nationally). They've never been in power federally, however they have been in power in some provinces. They seemed popular in Manitoba, though not much good has ever happened with the province. The last time they were in power in Ontario, the province was in a mess (though it is in a bigger mess now with the Liberals). I don't know much about when BC had them in. So do you need a workers party? Doesn't hurt to have the option, however I'd be extremely cautious on ever voting for them.
yes the U.S. does... but We already have one: http://www.workersparty.org/wp-draft-program.html Fun fact for the day... we don't have to vote dem. or rep. Did you know we have a long list of political parties who exist both on the municipal and national level? http://en.wikipedia.org/wiki/List_of_political_parties_in_the_United_States#Major_parties