I love the Big Bang Theory. It's the first mainstream show (In the US) that i believe really celebrates geeks. Other shows have had geek characters before, but all they do is wear headgear, shout Star Wars quotes and have voice problems. They're to be laughed at rather than with. Geeks in the BBT are the protagonists, they are the people you follow.
And the writers actually take the time to get everything right. The subtle jokes, and not so subtle jokes are researched and taken seriously. And geek icons like Stan Lee, Woz of course and Wil Wheaton are celebrated on the show, not brought on to be laughed at. In fact if you've got the time, look at Wil Wheatons blog where talks about the BBT, and he does nothing but praise it. He's a big self-confessed geek himself.
The only other show i think does it better is 'The IT Crowd'. Which i believe was first, it came out a year or 2 before. The geek jokes are quite a bit more subtle in that show. I hear you're getting your own version in America soon. That should be.....awful... given past Brit remakes.