Im ashamed to admit that last week I was sorting someone win8 laptop and I installed a copy of some software from CNET because I couldnt find it elsewhere. I was trigger happy with the install because it was a program that I knew was ok. But before I knew it I'd installed their stupid CNET downloader and associated junk carp.
Luckily I was easily able to clean it out before returning laptop to the owner.
I usually use http://www.majorgeeks.com/
as they don't use their own installer, and even warn you if the software contains any additional "optional" adware installs.