I track around 500 websites through their RSS feeds but here’s my list of favourite sources. I did try to categorise them but it’s too hard.

AdVerbatims
Seth’s Blog
Advertising Slogan Generator
Current
Ads of the World
Cute Overload
Mixx
Stuff On My Cat
Bali Street Dog Fund
National Underwater and Marine Agency
Download Squad
Lifehacker
ReadWriteWeb
The Unofficial Apple Weblog
10 Minute Mail
BugMeNot
MapLip
Glumbert
Ninjawords
Open Source Mac
Open Source Windows
Urban Dictionary
Freebasey
Alien Loves Predator
Amaztype
Alexandra Rawlinson
VIRB
Society of the Cusslermen
Skreemr
The Secret Diary of Steve Jobs
Drunkmenworkhere
TED blog
Engrish
Frank Lang
Group Hug
Yugop
SlideShare
Wired
Techmeme
Shoutwire
Slashdot
Techdirt
McCann Sydney