Good news for the GOP:
The results, obviously. They get to set the tone for the next 2 years.
States like West Virginia, South Dakota, and Arkansas are starting to fall in line with their presidential voting patterns in the Senate.
Strong pickups at the state level.
In the Senate and House game, the GOP is starting to create a stranglehold on both houses.
Good news for the Dems:
Yes, there is good news. North Carolina and Georgia were closer than expected. 8 points in Georgia in a non-presidential year is not bad. It is possible that if there is a strong Democratic candidate that Georgia could start turning purple in the next election cycle. North Carolina has affirmed its purple status. In the presidential game, the Democrats are starting to go into a strong ahead.
A note on Georgia, the Dems had their best possible candidates with good name recognition -- Sam Nunn's daughter for Senate against a pretty poor GOP Candidate who embraced outsourcing (which I think is a valid business activity, but sounds bad in a campaign) and Jimmy Carter's grandson for governor. Neither could keep it under 50% to force a runoff.
In North Carolina, Hagen was favored to win, slighlty ... at least in the RCP average and Nate Silver's site.
In other good GOP news, they were expected to drop governorships and as of now, they picked up a net 3 (Lost PA, won in MD, MA, AR, and IL) 3 of those being blue states and the Clintons campaigned hard in Arkansas for the 2 races there.
Wendy Davis and her allies spent a ton of money in TX, and she lost big. The GOP with weak candidates did really well in VT (a repudiation of the Health Care plan there), OR (more to do with some recent scandals than anything else).
When the dust settles on the State Legislatures, the GOP will pick up more houses(both houses in Nevada and West Virginia, the house in MN, others are still undecided) as well as gain some super majorities in others, and possible eliminate a Dem super majority in CA and IL.
There is a ton of stuff that was bottled up in the Senate for the last year that passed the House with decent amounts of Dem support (things like Keystone XL, repeal of a Medical Device tax, work requirements for welfare, etc). I would expect all those smaller things to get through fairly quickly and we will see what Obama does
The window for doing anything is January to October (at the latest), after that everything becomes about 2016. Congress will take a stab at one big ticket item (tax reform, immigration reform, etc).