Seretogis, suggesting that there are more than two influential parties, and therefore a multiparty system, is like arguing that a falling tree makes a sound when you aren't there to hear it. Here's a link on that subject:
http://usinfo.state.gov/products/pub...04/parties.htm
Among other things, the article points out that "Every president since 1852 has been either a Republican or a Democrat, and in the post-World War II era, the two major parties' share of the popular vote for president has averaged 94.8 percent." 5.2% of the vote spread out among multiple other parties doesn't make for a multiparty system of government.
Interestingly, there is a discussion of the inherent distrust of political parties as a reason for the two party system.