Considering The Big Bang Theory got very little critical acclaim when it first premiered last year, the critics really have warmed up to this show. TV Week did their annual summer poll of critics to see what they thought was the best (and worst) TV shows on TV, and The Big Bang Theory was voted the 14th best show on TV. See here for the results :

http://www.tvweek.com/2008/07/06/CriticsPollBestWorstweb.pdf