The majority of virusses spread via pirated software and other crap people download over P2P networks.
Email virusses used to be big but have been on the decline for a year or more.Direct infection through websites is low and generally not viral in nature but limited to installation of spyware or trojans that are usually not self replicating (though they may take actions to trick others into infecting themselves) and therefore don't class as virusses.
You can play 'games' with voting and listening to uninformed opinion, but if you listen to this fella instead you'll get the truth! :D