What is the most influential factor in a wine's flavor?

There are clusters of winemaking and viticultural factors that positively and negatively affect the taste of wine, but I can’t imagine a singular element that has a more profound affect on flavor than that of the grape variety itself. One can certainly argue that manipulative enological interference can mask varietal character, but disastrous situations aside, are there any vinous constituents that have more impact on wine’s flavor than that of the grape variety(s) selected?