On the Democratic front, president Obama has made it clear that while he is willing to compromise, he is not going to be bashful about using the veto ( the Republicans do not have the 60 votes to over-ride a veto). Immigration reform is front and center for Obama, while the Republicans are fulminating about the Health Care act. Mitch McConnell who has spent the last six years saying "no" to everything Obama, is not going to change his tactics now that he is majority leader in the Senate, and Boehner has his hands full trying to ward off the Tea-Partyers. In foreign policy, they are going to be more hawkish than the president and the still bitter McCain will be all over the place criticising anything that Obama does or try to do. They will push for an extended war against ISIL, even supporting ground troops, so Obama will have his way ( by the way, he is sending 1,500 more "trainers").
The congressional- military- industrial complex and the plutocrats are back in full force, helped by the millions spent by the Koch bros. and their corporate buddies and they will be looking to the Republicans to deliver on tax cuts, Keystone, fracking, less control on emissions and trade. It will be hot and heavy, with protestations, accusations, blame-gaming, back and forth and little will get done by Congress but Obama will act on immigration reform ( great for the Democrats with Latinos and minorities), defend the Health Care Act and continue his foreign policy ( even making more overtures with Iran , while the Israel lobby fumes)
It's all about 2016. The Republicans got their mid-term wish, for senate control, but this will come back to haunt them. The divisions and the rancor will be deafening. They will tear themselves apart, vying for the candidacy of the party, much to the delight of the Democrats. The Republicans made promises that they cannot deliver. Gerrymandering will allow them to hold on to the House, but the Presidency will belong to the Democrats.