A lot of people seem to think that, if the GOP can win both Houses of Congress, all will be "right" with the world. Nothing could be further from the truth.
First, a simple majority in both the Senate and the House of Representatives won't be enough to override an Obama Veto. The GOP will still need a 60 vote majority in the Senate to do that. At best, the Republicans might only gain a slim majority in the Senate. For that very reason, don't expect legislation such as killing the remainder of the Stimulus Package, the overturning of ObamaCare, Financial Re-Regulation or Cap and Trade to get past Obama's veto without some significant help from Democrats. I just don't see Democrats assisting that effort after having put their jobs on the line to pass all that legislation.
Secondly, unlike Clinton, when he lost both Houses of Congress, don't expect the President to resolve himself to work with a Republican lead Congress. Obama isn't the pragmatic animal that Clinton was. He's an ideologue who has already gone on record saying he doesn't mind being a one-term President.
Lastly, a majority control of Congress by the GOP might actually hurt them. That's because Obama will constantly campaign against the GOP's lack of legislative responsibility in blocking his agenda. He's already doing that to influence public opinion and the GOP doesn't even have a majority.
In my opinion, the best thing for the Republicans, is to win the House and weaken, but not completely win the Senate. This will nullify Obama and his radical agenda. Also, it will somewhat disarm his argument that the GOP are always blocking his legislation. Then, I think the focus should be to oust Obama and take a 60-vote majority in 2012.