My analysis thus far:
Likely Democratic Gains:
Connecticut
Likely Democratic Holds:
Delaware
Hawaii (well, starting to become shaky)
New Mexico
Virginia (I have a slightly queasy feeling)
California
Maryland
Michigan (a bit shaky)
Minnesota
New Jersey (meh)
New York
Pennsylvania
Vermont (well, Independent, but Sanders caucuses with the Dems)
Rhode Island
West Virginia
Ohio (slightly shaky)
Missouri (slightly shaky)
Washington
Likely Republican gains:
Wisconsin
Nebraska (not that it matters, since Ben Nelson is basically a Republican anyway)
Montana
Likely Republican Holds:
Texas
Indiana (unless Mourdock wins the Republican primary, oh, what fun
)
Maine (unless one of Snowe's challengers wins the primary, that would also be fun
)
Mississippi
Tennessee
Utah
Wyoming
Toss-ups:
Florida (leaning Democrat)Massachusetts (leaning Republican)Nevada (leaning Republican)North Dakota (leaning Republican)Arizona (leaning Republican)
So if things all go according to current leanings, the balance between the Left (aka the Democrats plus Sanders) and the Republicans will be exactly 50/50. In order for the Democrats (plus Sanders) to retain their (almost inevitably reduced) majority, they will need to take one or more of the Republican leaning toss-ups (I really wanna see Scott Brown kicked out lol). Or Lugar or Snowe can loose their primaries to their Tea Party challengers, thus handing the Democrats the seat on a golden platter.