If you think you don't need an Anti-Virus then good luck with your infected pc.
I visit maybe 1 or 2 infected sites a year (Usually for serial keys and keygens, which i clean strait away) but yet i may get something malicious on my computer every few months or so.
ccleaner caused me some problems. i cant remember what it is that it cleaned but it multiplied my boot time by like 10. i had to re-format my hdd to fix it.
i like nod32. spybot is okay too.