@Quinn phil,
I would choose the 1st, 4th, 5th, 9th, and 14th amendments.
1st amendment - I think this is a pretty standard element of the bill of rights (first ten amendments)that needs to be explicitly stated. You are entitled to religion, speech, press, assembly, and petition. It is also one of the most developed and widely interpreted of the bill of rights, so that being the case, the necessity dictates the incorporation.
4th amendment - The provision against unlawful search and seizures. If anything, this is an affirmation of the rights to possession and even ownership. It also presupposes our legal framework following in the 5th amendment.
5th amendment - Right to trial by grand jury (of peers), double jeopardy, self incrimination, and due process. I think most everyone would agree the importance of a legal framework and the presumption of due process. You could not have the seventh amendment (oddly popular on this thread) without the 5th amendment in place to stabilize and further legitimize it.
9th amendment - Basically, this amendment asserts, or more specifically limits congress to a set state of enumerated powers (those laid down in the constitution and not implied in the result of a given absence). In the actual constitution, there is a "necessary and proper clause" which in some respects could give congress the right to basically trample on the rights of the people. So think of this is some respects as an amendment to affirm the fact that amendments are amendments. Incidentally, this amendment is also a two-for-one (a twofur?), because it necessarily implies the tenth amendment wherein powers are reserved to the states or the people not otherwise attributed to the federal government.
14th amendment - This amendment pertain to citizen ship, privileges and immunities, due process, and equal protection under the law. This is honestly one of the biggest and most historically developed laws in the history of the United States of America? reaching far back into colonial jurisprudence. Who is qualified to be a citizen (slavery), what rights should those citizens have (state action), who has more equal rights than others (separate but equal issues), etc.? Huge issues in American history surrounding this amendment? which was carefully left optional at the forming of the constitution and widely interpreted even today. This is also arguably a twofur, since its section two on appointment was superseded by the 26th amendment.