Symantec has listed some of the worst and dirtiest websites. Beware of these.

Code:
Symantec?s Web site ratings service Norton Safe Web presents the Dirtiest Web Sites of Summer 2009 ? the top 100 infected sites based on number of threats detected by Norton Safe Web as of August 2009.
Sample of Dirtiest Web Sites:
17ebook.com
aladel.net
bpwhamburgorchardpark.org
clicnews.com
dfwdiesel.net
divineenterprises.net
fantasticfilms.ru
gardensrestaurantandcatering.com
ginedis.com
gncr.org
hdvideoforums.org
hihanin.com
kingfamilyphotoalbum.com
likaraoke.com
mactep.org
magic4you.nu
marbling.pe.kr
nacjalneg.info
pronline.ru
purplehoodie.com
qsng.cn
seksburada.net
sportsmansclub.net
stock888.cn
tathli.com
teamclouds.com
texaswhitetailfever.com
wadefamilytree.org
xnescat.info
yt118.com


More details here :

Code:
http://safeweb.norton.com/dirtysites