From what I have seen of both "The Big Bang Theory" and "The IT Crowd" I am going to say that "The IT Crowd" is the geekiest. "The Big Bang Theory" has more obvious jokes in the script wile "The IT Crowd" has jokes that are more thought out and that half the time you would not see coming...
Chuck Bartowski (Zachary Levi) is a twenty-something in Burbank, CA who works as a computer expert at the Nerd Herd
yeah this guy... he have the cia computer inside his brain... lol
Numb3rs is a pretty geeky show in my opinion. There is even book about Numb3rs that explains the math used in the episodes and how the math was originally thought up and by who.