Barack Obama won the 2008 election in a landslide. The Senate had 59 Senators (60 after Spector switched parties) and the house had 257 Democrats. The only reason that they had to make a bill bipartisan was to either avoid a filbuster in the Senate, or to attempt to foster goodwill from Republicans. Elections have consequences and in 2009 Democrats had won the right to pass a bill without widespread Republican support.
The stimulus package cannot in any right be called a bipartisan package. The stimulus was backed by the democrats, and heavily opposed by republican leaders in the GOP. A bipartisan bill successfully accounts for the opinion of both parties in our bipartisan system, not one. Obama pushed the bill through the House and the Senate without support from Republicans.