Colorado: This is one of only two feasible options the GOP has for gains in 2016. This one would still be an uphill battle between Presidential year turnout and demographics of the state. No one significant yet to officially jump in on the GOP side and it looks like Bennett will avoid major Democratic Primary opposition. The GOP hopes to recruit Rep. Coffman to run. At this point, this race looks more winnable for Democrats.
Connecticut: This state is just about as blue as it gets. Incumbent Richard Blumenthal will likely be very difficult for the GOP to unseat. He won by 12% in 2010 and will likely win by a larger margin in 2016.