Many observers noted during the 2004 Presidential elections in the United States how entire regions of the nation were either "blue" for Democrat states or "red" for Republican states. Germany looks much the same, with "red" representing SPD districts and "black/gray" representing CDU-CSU districts:
2005 Results by District: Southern Germany primarily voted CDU-CSU; North-central and eastern Germany largely went to the SPD. (source)
Reunification has had very clear political consequences for Germany. Without the eastern voters, the SPD would have clearly lost the past two elections.
Unemployment fears also seem to have a correspondence to voting patters.
Fear of Unemployment in Germany last year: Dark red zones represent high unemployment fears while lighter zones represent lower unemployment fear. The areas where unemployment is most feared also tend to be the areas where unemployment is in fact highest. (source) (Hattip Konrad)
As in 2002, fear played a major role in this election. In 2002 it was fear of war in Iraq. This time the fears centered mainly around unemployment issues and economic reforms to the German social welfare state.
Anyway, once the media circus and the hype die down, the fact remains that the SPD was the largest overall loser of votes in this election and that the SPD has lost almost every state election over the past four years. The SPD also lost a significant chunk of its voters to the "Left/PDS" party throughout Germany. The reason that the SPD still looks like a winner despite it all is explained by the low expectations on Schroeder and the high expectations on Merkel. Merkel clearly underperformed and also lost votes and Schroeder indeed had a strong surge at the end. But this SPD loss is still a loss and sober political reality will govern Germany's unclear and divided future.
Stay tuned...anything can still happen...