In Florida, Debbie Wasserman Schultz has already made it clear that she will not try to run for Senate in 2016. Alan Grayson has said that he might, but he is embroiled with attempting to annul his marriage on grounds of bigamy. Patrick Murphy, who unseated incumbent Alan West in 2012 and won a decisive reelection in 2014 in a red leaning district, has declared his candidacy for Senate. While this makes his house seat a good pickup opportunity for the GOP in 2016, this makes the Senate seat much more in play. It is widley expected that Senator Rubio will not run for reelection and decide to run for the GOP nomination for President instead. While there are plenty of potential Republicans that could run and win: without Rubio, this seat is much for "getable" for team blue.
Today, Senator Dan Coats has announced his retirement. This is a boost to Democratic prospects in this state for 2016. While it will still be an uphill battle, it is much more feasible. If Democrats can convince the (still in his 50's) former Senator Evan Bayh to run for his old seat (that he retired from in 2010 instead of running for reelection), this seat becomes a VERY good (possible even better than Illinois at this point) pickup chance for Democrats. Bayh still has 10 million on hand (in 2012, Dems won the Senate seat with only 6 million raised) and maintains a 60% favorability rating. He has said that he is not interested in running again "at this time," but that may very well change with Coats out of the race.