The C3 still holds the record for the longest production run of any generation Corvette. It was the generation that saw the Corvette "grow-up" from being a powerful track car and Le Mans racer to an iconic sports car synonymous with the American Dream.
Despite its popularity, the second-gen Corvette holds the record for the fewest number of production years of any generation Corvette. The most valuable examples of the C2 Corvette live sort of like "bookends" at the start and finish of second-gen production.
The early C4's had their problems, what with the 1984 Cross-Fire Injection and its unusual 4+3 manual transmission. By the late 1980's, the fourth-generation Corvette had evolved into a more desirable automobile, thanks in part to the arrival of the ZR-1.
While there are some early C1 Corvettes out there that are exceedingly rare and prohibitively expensive, there are plenty of first-generation Corvettes - especially those between 1959 and 1961 - that are well within the range of most budgets.