The idea is similar to the List the US/UK/Danish/Filipino Heads of Government threads, except this one will detail the compositions of the Senate at only one (or two) time periods at a time - after all, the (modern) Senate has 100 members. We do one state at a time.
2012: Two Decades of Reform
VT-1: Howard Dean (R gain)
VT-3: Jerry Greenfield (D)