First , one cannot minimize the size of this victory both in terms of scope and spread. Had Chambliss lost the Democrats would have likely been further energized to do whatever was neccessary to steal the Minnesota Senate seat thus giving them the filibuster proof majority that would we all dread.
Secondly, it was a wake up call moment for the left. They realized that even though they have made significant gains in the last 4 years, they are far from invincible. Ludicris and Clinton were no match for Sarah Palin in Georgia as Chambliss crushed Martin by 14% points. BTW just to give you a feel for how the base feels, McCain drew crowds of around 1000 people, Romney less than 500 and Palin 4-5000.
This win should point out one very important fact to the Republican leadership....You can't win elections without a high percentage turnout of your base and Noonan/Parker/McCain type centrist compromisers DON"T turnout the base.