It is worth remembering that despite Scott Brown's election as a Republican Senator from Massachusetts, the Northeast Republicans are still only breaking even this between election cycle. Arlen Spectre of Pennsylvania switched to the Democratic Party in 2009.
The House has likewise seen one flip in each direction since the last election. Democrats gained a seat in New York, but lost one in Alabama.
There are just as many Democrats in the U.S. House and U.S. Senate now as there were immediately following the 2008 election that brought President Obama to power and gave Democrats majorities in the House and Senate last seen in the Civil Rights era.