Poll #1: http://csnbbs.com/thread-829175.html
Poll #3: http://csnbbs.com/thread-829328.html

As I explored in a previous thread, there are 84 pairs of FBS teams that have played one another annually for at least 30 years and are still actively playing one another. Some are very obviously what one would call "essential" rivalries, meaning both teams would likely seek to retain the matchup each year even in the event of a realignment that separated them into different divisions or conferences. In some cases, this has already happened, or they were never in the same conference/division to begin with.

Other pairs aren't particularly essential and may primarily be the result of sharing a conference/division and not any strong desire to play. These matchups would be sacrificed as annual games in the event of a realignment that separated the teams.

The line between essential and non-essential is rather blurry, so I thought I'd post a poll to see what the realignment forum thinks. Actually, I have to post two polls, because the limit on poll options is 16.

Here are the matchups which may or may not be essential. The year in parentheses is the first year of the current run of annual matchups.

Air Force/Wyoming (1980)
Alabama/LSU (1964)
Alabama/Mississippi State (1948)
Arkansas/Ole Miss (1981)
Baylor/Texas (1945)
Baylor/Texas Tech (1956)
California/USC (1926)
Central Michigan/Eastern Michigan (1972)
Central Michigan/Western Michigan (1973)
Clemson/Georgia Tech (1983)
Clemson/NC State (1971)
Duke/Georgia Tech (1933)
Duke/Virginia (1963)
Duke/Wake Forest (1967)
Eastern Michigan/Western Michigan (1978)
Florida/LSU (1971)
Georgia/Vanderbilt (1968)
Iowa/Minnesota (1931)
Iowa State/Kansas State (1917)
Kentucky/Tennessee (1944)
Kentucky/Vanderbilt (1953)
LSU/Mississippi State (1944)
LSU/Ole Miss (1945)
NC State/Wake Forest (1910)
North Carolina/Virginia (1919)
Ole Miss/Vanderbilt (1970)
Pittsburgh/Syracuse (1955)
Stanford/UCLA (1946)
Texas/Texas Tech (1960)
Toledo/Western Michigan (1950)

These are what I would consider essential rivalries:

Air Force/Army (1971)
Air Force/Colorado State (1978)
Air Force/Navy (1972)
Alabama/Auburn (1948)
Alabama/Tennessee (1944)
Arizona/Arizona State (1946)
Army/Navy (1930)
Auburn/Georgia (1944)
Bowling Green/Toledo (1948)
California/Stanford (1946)
California/UCLA (1933)
Cincinnati/Miami-OH (1945)
Clemson/South Carolina (1909)
Colorado State/Wyoming (1946)
Duke/North Carolina (1922)
Florida/Florida State (1958)
Florida/Georgia (1944)
Florida State/Miami-FL (1969)
Georgia/Georgia Tech (1925)
Illinois/Northwestern (1927)
Indiana/Purdue (1920)
Iowa/Iowa State (1977)
Kansas/Kansas State (1911)
Miami-OH/Ohio (1945)
Michigan/Michigan State (1945)
Michigan/Ohio State (1918)
Minnesota/Wisconsin (1907)
Navy/Notre Dame (1927)
New Mexico/New Mexico State (1946)
NC State/North Carolina (1953)
Notre Dame/USC (1946)
Oklahoma/Oklahoma State (1910)
Oklahoma/Texas (1929)
Mississippi State/Ole Miss (1944)
Oregon/Oregon State (1945)
Tennessee/Vanderbilt (1945)
Stanford/USC (1946)
UCLA/USC (1936)
Virginia/Virginia Tech (1970)
Washington/Washington State (1945)

And I'm fairly certain these are not essential:

Auburn/Mississippi State (1955)
Ball State/Central Michigan (1977)
Ball State/Eastern Michigan (1973)
Ball State/Toledo (1975)
Central Michigan/Toledo (1975)
Clemson/Wake Forest (1953)
Eastern Michigan/Toledo (1977)
Florida/Kentucky (1967)
Georgia/Kentucky (1956)
Georgia Tech/North Carolina (1980)
Georgia Tech/Virginia (1982)
Iowa State/Kansas (1932)
Kent State/Miami-OH (1955)
Kent State/Ohio (1949)