1) Wealthy NE suburban and exurban districts where moderate Republicans and independents threw the GOP overboard due to social liberalism and opposition to the war in Iraq. This explains the losses in CT-02, CT-05, NH-01, NH-02, NY-19, NY-20, NY-24, PA-04, PA-07, PA-08 and PA-10. The GOP was wiped out in the North East. These losses were an explicit denunciation of social conservatism and the Iraq war. This thesis is further supported by the fact the GOP support among economically successful and wealthy males fell from 60% in 2004 to 46% in 2006.
2) Mid-Western (upper South) districts populated by Reagan Democrats who wanted more economically liberal policies (opposition to free trade etc.) and were opposed to the Iraq war. This explains the losses in IN-02, IN-08, IN-09, KY-03, NC-11 etc.
3) Districts with incumbents connected to scandals and corruption; FL-16 (Foley), AZ-05 (Hayworth), CA-11 (Pombo), TX-22.
These examples constitute a bulk Republican house losses. Frankly, I'm most concerned about the loss of Republican support among successful, wealthy upper-middle class males (small businessmen, professionals etc.) who have traditionally been the backbone of Republicanism and provided much of the grass roots funding for the party.
I think a more telling reason may be the Reagan Democrats abandoned the GOP ... or should I say the GOP abandoned them.
Since you believe social conservatism was our downfall, I appreciate it if you would tell us what you think the GOP should stand for.