There were two distinctive t-shirts I saw at BlizzCon this year. The first was worn by Greg Street, a.k.a. Ghostcrawler. It featured his pet crab that he refers to often enough. If I recall correctly, he lost it in the Sunken Temple.
The second was worn by Rob Pardo, the Executive VP of Game Design at Blizzard. It featured an image of a rainbow above the words "Diablo 3." It also had unicorns and flowers on it. Very Barbie like.
While both shirts have their place, I think it'd be fun to know – which one would you rather have? Personally, I want the D3 shirt Pardo had on. Hilarious stuff there. But Ghostcrawler has gained quite a following as well. Vote for your favorite gear and be heard!
Update: It's not being worn by a Blue, and therefore isn't poll-worthy, but we enjoyed this shirt, too.